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class="vector-toc-numb">2</span> <span>Preventive devices</span> </div> </a> <ul id="toc-Preventive_devices-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Regulatory_requirements" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Regulatory_requirements"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Regulatory requirements</span> </div> </a> <ul id="toc-Regulatory_requirements-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Partial_list_of_backflow_prevention_devices_and_assemblies" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Partial_list_of_backflow_prevention_devices_and_assemblies"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Partial list of backflow prevention devices and assemblies</span> </div> </a> <ul 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0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-More_citations_needed plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, 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Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Backflow+prevention+device%22">"Backflow prevention device"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Backflow+prevention+device%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Backflow+prevention+device%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Backflow+prevention+device%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Backflow+prevention+device%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Backflow+prevention+device%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">March 2013</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Back_siphon_example_hosepipe_up_hill.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Back_siphon_example_hosepipe_up_hill.svg/220px-Back_siphon_example_hosepipe_up_hill.svg.png" decoding="async" width="220" height="131" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Back_siphon_example_hosepipe_up_hill.svg/330px-Back_siphon_example_hosepipe_up_hill.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Back_siphon_example_hosepipe_up_hill.svg/440px-Back_siphon_example_hosepipe_up_hill.svg.png 2x" data-file-width="632" data-file-height="377" /></a><figcaption>In this situation, dirty water from the hillside pool will <i>back-<a href="/wiki/Siphon" title="Siphon">siphon</a></i> or <i>back-flow</i> down the <a href="/wiki/Hosepipe" class="mw-redirect" title="Hosepipe">hosepipe</a> and into the clean water tank. To prevent this from happening, the house's external <a href="/wiki/Tap_(valve)" title="Tap (valve)">tap</a> should be fitted with a backflow prevention device.</figcaption></figure> <p>A <b>backflow prevention device</b> is used to protect <a href="/wiki/Potable_water" class="mw-redirect" title="Potable water">potable water</a> supplies from contamination or pollution due to <a href="/wiki/Backflow_(plumbing)" class="mw-redirect" title="Backflow (plumbing)">backflow</a>. </p><p>In <a href="/wiki/Water_distribution_system" title="Water distribution system">water distribution systems</a>, water is normally maintained at a significant pressure to enable water to flow from the tap, shower, or other fixture. Water pressure may fail or be reduced when a water main bursts, pipes freeze, or there is unexpectedly high demand on the water system (for example, when several <a href="/wiki/Fire_hydrant" title="Fire hydrant">fire hydrants</a> are opened). Reduced pressure in the pipe may allow contaminated <a href="/wiki/Ground_water" class="mw-redirect" title="Ground water">water from the soil</a>, from storage, or from other sources to be drawn up into the system. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Terminology">Terminology</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=1" title="Edit section: Terminology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Backflow</b> means the undesirable reversal of flow of a liquid, gas, or suspended solid into the potable water supply; a <b>backflow preventer</b> is designed to keep this from happening. Points at which a potable water system connects with a non-potable water system are called <b>cross connections</b>. Such connections occur naturally in appliances such as <a href="/wiki/Clothes_washer" class="mw-redirect" title="Clothes washer">clothes washers</a> and <a href="/wiki/Dishwasher" title="Dishwasher">dishwashers</a>, but they must be carefully designed and installed to prevent backflow. Another common location for a backflow preventer is the connection of a <a href="/wiki/Fire_sprinkler" title="Fire sprinkler">fire sprinkler</a> system to a water main, to prevent pressurized water from flowing from the fire suppression system into the public water supply. </p><p><b>Back-siphonage</b> occurs when higher pressure fluids, gases, or suspended solids move to an area of lower pressure fluids. For example, when a <a href="/wiki/Drinking_straw" title="Drinking straw">drinking straw</a> is used to consume a beverage, suction reduces the pressure of fluid inside the straw, causing liquid to move from the cup to inside the straw and then into the drinker's mouth. A significant drop of pressure in a water delivery system creates a similar suction, <i>pulling</i> possibly undesirable material into the system. This is an example of an <b>indirect cross-connection</b>. </p><p><b>Back-pressure</b> occurs for example when air is blown through the straw and bubbles begin to erupt at the submerged end. If, instead of air, <a href="/wiki/Natural_gas" title="Natural gas">natural gas</a> had been forced into a potable water tank, the gas in turn could be carried to a kitchen faucet. This is an example of a <b>direct cross-connection</b>, with undesirable material being <i>pushed</i> into the system. </p><p>Back pressure can force an undesirable contaminant to enter potable water piping. Sources of back pressure may be boilers, heat exchanging equipment, power washing equipment, fire sprinklers, or pumps in the water distribution system. In some cases there may be an almost continuous risk of overcoming the static water pressure in the piping. To reduce the risk of contamination, a backflow preventer can be fitted. A backflow preventer is also important when potentially toxic chemicals are used, for instance for commercial/industrial <a href="/wiki/Descaling" class="mw-redirect" title="Descaling">descaling</a> of boilers, or when chemical <a href="/wiki/Bleach" title="Bleach">bleaches</a> are used for residential power washing. </p><p>A closely related device is the <b><a href="/wiki/Backwater_valve" title="Backwater valve">backwater valve</a></b>, which is designed to prevent <a href="/wiki/Sewage" title="Sewage">sewage</a> from backing up into a building and causing basement flooding.<sup id="cite_ref-Backwater_1-0" class="reference"><a href="#cite_note-Backwater-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Preventive_devices">Preventive devices</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=2" title="Edit section: Preventive devices"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Verifiedbackflow.jpeg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/54/Verifiedbackflow.jpeg/220px-Verifiedbackflow.jpeg" decoding="async" width="220" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/54/Verifiedbackflow.jpeg/330px-Verifiedbackflow.jpeg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/54/Verifiedbackflow.jpeg/440px-Verifiedbackflow.jpeg 2x" data-file-width="499" data-file-height="332" /></a><figcaption>Backflow prevention device</figcaption></figure> <p>The simplest, most reliable way to provide backflow prevention is to provide an <a href="/wiki/Air_gap_(plumbing)" title="Air gap (plumbing)">air gap</a>. An air gap is simply an open vertical space between any device that connects to a plumbing system (like a valve or faucet) and any place where contaminated water can collect or pool. A simple air gap has no moving parts, other than flowing water. Many <a href="/wiki/Plumbing_code" title="Plumbing code">plumbing codes</a> specify a minimum air gap distance required for various circumstances, such as a drain connection for a dishwasher, e.g., <a href="/w/index.php?title=BS_6282&action=edit&redlink=1" class="new" title="BS 6282 (page does not exist)">BS 6282</a>. </p><p>Alternatively, a specialized backflow preventer valve may be installed at strategic locations in the plumbing system wherever there is a risk of contaminated fluids entering the water supply pipes. These valves are used where there is not sufficient vertical clearance or physical space to install an air gap, or when pressurized operation or other factors rule out use of an air gap. Because these valves use moving parts, they are often required to be inspected or tested periodically. </p> <div class="mw-heading mw-heading2"><h2 id="Regulatory_requirements">Regulatory requirements</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=3" title="Edit section: Regulatory requirements"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To prevent contamination due to back pressure, many health regulatory regimes require an air gap or mechanical backflow prevention assembly between the delivery point of mains water and local storage or use.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Where submerged mains inflow is permitted,<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="The text near this tag needs further explanation. (March 2013)">further explanation needed</span></a></i>]</sup> a backflow prevention assembly is required, which protects the potable water system from contamination hazards. A <a href="/wiki/Check_valve" title="Check valve">check valve</a> is a basic form of backflow prevention, but often more complex devices are required because check valves are not considered to be reliable, when compared to more sophisticated devices with redundancies and reduced-pressure zones.<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="The text near this tag needs further explanation. (September 2015)">further explanation needed</span></a></i>]</sup> </p><p>In many countries. approved backflow prevention assemblies are required by law, and must be installed in accordance with plumbing or <a href="/wiki/Building_code" title="Building code">building codes</a>.<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:AUDIENCE" class="mw-redirect" title="Wikipedia:AUDIENCE"><span title="An editor has requested that an example be provided. (February 2012)">example needed</span></a></i>]</sup> A typical backflow assembly has test cocks and shut-off valves, and must be tested when installed, if relocated or repaired, and also on a periodic basis.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup> </p><p>In the US, the <a href="/wiki/United_States_Environmental_Protection_Agency" title="United States Environmental Protection Agency">Environmental Protection Agency</a> (EPA) holds local water suppliers responsible for maintaining a certain amount of purity in potable water systems. Many states and/or local municipalities require annual testing of backflow prevention assemblies. In most cases, the law requires a double check (DC), reduced pressure principle device (<a href="/wiki/Reduced_pressure_zone_device" title="Reduced pressure zone device">RP</a>) device, or an air gap when backflow prevention is mandated.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2013)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Partial_list_of_backflow_prevention_devices_and_assemblies">Partial list of backflow prevention devices and assemblies</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=4" title="Edit section: Partial list of backflow prevention devices and assemblies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Air_gap_(plumbing)" title="Air gap (plumbing)">Air gap</a> (AG the purest form of backflow prevention)</li> <li><a href="/wiki/Atmospheric_vacuum_breaker" title="Atmospheric vacuum breaker">Atmospheric vacuum breaker</a> (AVB)</li> <li><a href="/wiki/Check_valve" title="Check valve">Check valve</a> (usually not a legally approved method of backflow prevention.)</li> <li><a href="/wiki/Chemigation_valve" title="Chemigation valve">Chemigation valve</a> (primarily used in agriculture)</li> <li><a href="/wiki/Double_check_valve" title="Double check valve">Double check valve assembly</a> (DCVA)</li> <li><a href="/wiki/Dual_check_valve" class="mw-redirect" title="Dual check valve">Dual check valve</a> (A dual check is not a testable device and is mainly used on residential customers)</li> <li><a href="/wiki/Pressure_vacuum_breaker_assembly" class="mw-redirect" title="Pressure vacuum breaker assembly">Pressure vacuum breaker assembly</a> (PVB)</li> <li><a href="/wiki/Reduced_pressure_zone_device" title="Reduced pressure zone device">Reduced pressure zone device</a> (RPZ)</li> <li><a href="/w/index.php?title=Spill_resistant_pressure_vacuum_breaker_assembly&action=edit&redlink=1" class="new" title="Spill resistant pressure vacuum breaker assembly (page does not exist)">Spill resistant pressure vacuum breaker assembly</a> (SPVB)</li> <li><a href="/wiki/Vacuum_breaker" title="Vacuum breaker">Vacuum breaker</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=5" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Backflow_(plumbing)" class="mw-redirect" title="Backflow (plumbing)">Backflow (plumbing)</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=6" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-Backwater-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-Backwater_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.absolutedp.com/backwater-valve-installation">"Backwater Valve Installation"</a>. Absolute Draining & Plumbing<span class="reference-accessdate">. Retrieved <span class="nowrap">9 October</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Backwater+Valve+Installation&rft.pub=Absolute+Draining+%26+Plumbing&rft_id=http%3A%2F%2Fwww.absolutedp.com%2Fbackwater-valve-installation&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABackflow+prevention+device" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.opsi.gov.uk/si/si1999/99114802.htm">"The Water Supply (Water Fittings) Regulations 1999"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100823022423/http://www.opsi.gov.uk/si/si1999/99114802.htm">Archived</a> from the original on 23 August 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">July 26,</span> 2010</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Water+Supply+%28Water+Fittings%29+Regulations+1999&rft_id=http%3A%2F%2Fwww.opsi.gov.uk%2Fsi%2Fsi1999%2F99114802.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABackflow+prevention+device" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Backflow_prevention_device&action=edit&section=7" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://www.iapmo.org">International Association of Plumbing and Mechanical Officials</a></li> <li><a rel="nofollow" class="external text" href="http://www.dwbp-online.com">Drinking Water & Backflow Prevention magazine</a></li> <li><a rel="nofollow" class="external text" href="http://www.abpa.org">The American Backflow Prevention Association</a></li> <li><a rel="nofollow" class="external text" href="http://www.usc.edu/fccchr">Foundation for Cross-Connection Control and Hydraulic Research</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul 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title="Special:EditPage/Template:Backflow"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Backflow_and_prevention" style="font-size:114%;margin:0 4em"><a href="/wiki/Backflow" title="Backflow">Backflow</a> and <a class="mw-selflink selflink">prevention</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Backflow prevention methods</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Atmospheric_vacuum_breaker" title="Atmospheric vacuum breaker">Atmospheric vacuum breaker</a></li> <li><a href="/wiki/Air_gap_(plumbing)" title="Air gap (plumbing)">Air gap</a></li> <li><a href="/wiki/Check_valve" title="Check valve">Check valve</a></li> <li><a href="/wiki/Chemigation_valve" title="Chemigation valve">Chemigation valve</a></li> <li><a href="/wiki/Double_check_valve" title="Double check valve">Double check valve</a></li> <li><a href="/wiki/Hydrostatic_loop" title="Hydrostatic loop">Hydrostatic loop</a></li> <li><a href="/wiki/Pressure_vacuum_breaker" title="Pressure vacuum breaker">Pressure vacuum breaker</a></li> <li><a href="/wiki/Reduced_pressure_zone_device" title="Reduced pressure zone device">Reduced pressure zone device</a></li> <li><a href="/wiki/Vacuum_breaker" title="Vacuum breaker">Vacuum breaker</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Plumbing" style="vertical-align: middle;;padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Plumbing" title="Template:Plumbing"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Plumbing" title="Template talk:Plumbing"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Plumbing" title="Special:EditPage/Template:Plumbing"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Plumbing" style="font-size:114%;margin:0 4em"><a href="/wiki/Plumbing" title="Plumbing">Plumbing</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Fundamental<br />concepts</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Air_gap_(plumbing)" title="Air gap (plumbing)">Air gap (plumbing)</a></li> <li><a href="/wiki/Backflow" title="Backflow">Backflow</a></li> <li><a href="/wiki/Compatibility_(chemical)" title="Compatibility (chemical)">Compatibility (chemical)</a></li> <li><a href="/wiki/Corrosion" title="Corrosion">Corrosion</a></li> <li><a href="/wiki/Drain_(plumbing)" title="Drain (plumbing)">Drain (plumbing)</a></li> <li><a href="/wiki/Drinking_water" title="Drinking water">Drinking water</a></li> <li><a href="/wiki/Fuel_gas" title="Fuel gas">Fuel gas</a></li> <li><a href="/wiki/Friction_loss" title="Friction loss">Friction loss</a></li> <li><a href="/wiki/Grade_(slope)" title="Grade (slope)">Grade (slope)</a></li> <li><a href="/wiki/Greywater" title="Greywater">Greywater</a></li> <li><a href="/wiki/Heat_trap" title="Heat trap">Heat trap</a></li> <li><a href="/wiki/Hydrostatic_loop" title="Hydrostatic loop">Hydrostatic loop</a></li> <li><a href="/wiki/Leak" title="Leak">Leak</a></li> <li><a href="/wiki/Neutral_axis" title="Neutral axis">Neutral axis</a></li> <li><a href="/wiki/Onsite_sewage_facility" title="Onsite sewage facility">Onsite sewage facility</a></li> <li><a href="/wiki/Pressure" title="Pressure">Pressure</a></li> <li><a href="/wiki/Sanitary_sewer" title="Sanitary sewer">Sanitary sewer</a></li> <li><a href="/wiki/Sewer_gas" title="Sewer gas">Sewer gas</a></li> <li><a href="/wiki/Sewage" title="Sewage">Sewage</a></li> <li><a href="/wiki/Sewerage" title="Sewerage">Sewerage</a></li> <li><a href="/wiki/Siphon" title="Siphon">Siphon</a></li> <li><a href="/wiki/Storm_sewer" class="mw-redirect" title="Storm sewer">Storm sewer</a></li> <li><a href="/wiki/Stormwater" title="Stormwater">Stormwater</a></li> <li><a href="/wiki/Surface_tension" title="Surface tension">Surface tension</a></li> <li><a href="/wiki/Tap_water" title="Tap water">Tap water</a></li> <li><a href="/wiki/Thermal_expansion" title="Thermal expansion">Thermal expansion</a></li> <li><a href="/wiki/Thermal_insulation" title="Thermal insulation">Thermal insulation</a></li> <li><a href="/wiki/Thermosiphon" title="Thermosiphon">Thermosiphon</a></li> <li><a href="/wiki/Trap_(plumbing)" title="Trap (plumbing)">Trap (plumbing)</a></li> <li><a href="/wiki/Venturi_effect" title="Venturi effect">Venturi effect</a></li> <li><a href="/wiki/Wastewater" title="Wastewater">Wastewater</a></li> <li><a href="/wiki/Water_hammer" title="Water hammer">Water hammer</a></li> <li><a href="/wiki/Water_supply_network" title="Water supply network">Water supply network</a></li> <li><a href="/wiki/Water_table" title="Water table">Water table</a></li> <li><a href="/wiki/Well" title="Well">Well</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Technology</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Brazing" title="Brazing">Brazing</a></li> <li><a href="/wiki/British_Standard_Pipe" title="British Standard Pipe">British Standard Pipe</a> (BSP)</li> <li><a href="/wiki/Cast_iron_pipe" title="Cast iron pipe">Cast iron pipe</a></li> <li><a href="/wiki/Chemical_drain_cleaners" title="Chemical drain cleaners">Chemical drain cleaners</a></li> <li><a href="/wiki/Compression_fitting" title="Compression fitting">Compression fitting</a></li> <li><a href="/wiki/Copper_tubing" title="Copper tubing">Copper tubing</a></li> <li><a href="/wiki/Crimp_(joining)" title="Crimp (joining)">Crimp (joining)</a></li> <li><a href="/wiki/Drain-waste-vent_system" title="Drain-waste-vent system">Drain-waste-vent system</a></li> <li><a href="/wiki/Ductile_iron_pipe" title="Ductile iron pipe">Ductile iron pipe</a></li> <li><a href="/wiki/Flare_fitting" title="Flare fitting">Flare fitting</a></li> <li><a href="/wiki/Garden_hose_thread" class="mw-redirect" title="Garden hose thread">Garden Hose Thread</a> (GHT)</li> <li><a href="/wiki/Gasket" title="Gasket">Gasket</a></li> <li><a href="/wiki/Hydronics" title="Hydronics">Hydronics</a></li> <li><a href="/wiki/Leak_detection" title="Leak detection">Leak detection</a></li> <li><a href="/wiki/National_Pipe_Thread" class="mw-redirect" title="National Pipe Thread">National Pipe Thread</a> (NPT)</li> <li><a href="/wiki/Nominal_Pipe_Size" title="Nominal Pipe Size">Nominal Pipe Size</a> (NPS)</li> <li><a href="/wiki/O-ring" title="O-ring">O-ring</a></li> <li><a href="/wiki/Oakum" title="Oakum">Oakum</a></li> <li><a href="/wiki/Pipe_(fluid_conveyance)" title="Pipe (fluid conveyance)">Pipe (fluid conveyance)</a></li> <li><a href="/wiki/Pipe_dope" title="Pipe dope">Pipe dope</a></li> <li><a href="/wiki/Pipe_support" title="Pipe support">Pipe support</a></li> <li><a href="/wiki/Plastic_pipework" title="Plastic pipework">Plastic pipework</a></li> <li><a href="/wiki/Push-to-pull_compression_fittings" title="Push-to-pull compression fittings">Push-to-pull compression fittings</a></li> <li><a href="/wiki/Putty" title="Putty">Putty</a></li> <li><a href="/wiki/Sealant" title="Sealant">Sealant</a></li> <li><a href="/wiki/Sewage_pumping" title="Sewage pumping">Sewage pumping</a></li> <li><a href="/wiki/Soldering" title="Soldering">Soldering</a></li> <li><a href="/wiki/Solvent_welding" class="mw-redirect" title="Solvent welding">Solvent welding</a></li> <li><a href="/wiki/Swaging" title="Swaging">Swaging</a></li> <li><a href="/wiki/Thread_seal_tape" title="Thread seal tape">Thread seal tape</a></li> <li><a href="/wiki/Threaded_pipe" title="Threaded pipe">Threaded pipe</a></li> <li><a href="/wiki/Tube_bending" title="Tube bending">Tube bending</a></li> <li><a href="/wiki/Water_heat_recycling" title="Water heat recycling">Water heat recycling</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Components</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Atmospheric_vacuum_breaker" title="Atmospheric vacuum breaker">Atmospheric vacuum breaker</a></li> <li><a href="/wiki/Automatic_bleeding_valve" title="Automatic bleeding valve">Automatic bleeding valve</a></li> <li><a href="/wiki/Automatic_faucet" title="Automatic faucet">Automatic faucet</a></li> <li><a class="mw-selflink selflink">Backflow prevention device</a></li> <li><a href="/wiki/Ball_valve" title="Ball valve">Ball valve</a></li> <li><a href="/wiki/Bleed_screw" title="Bleed screw">Bleed screw</a></li> <li><a href="/wiki/Booster_pump" title="Booster pump">Booster pump</a></li> <li><a href="/wiki/Butterfly_valve" title="Butterfly valve">Butterfly valve</a></li> <li><a href="/wiki/Check_valve" title="Check valve">Check valve</a></li> <li><a href="/wiki/Chemigation_valve" title="Chemigation valve">Chemigation valve</a></li> <li><a href="/wiki/Chopper_pump" class="mw-redirect" title="Chopper pump">Chopper pump</a></li> <li><a href="/wiki/Circulator_pump" title="Circulator pump">Circulator pump</a></li> <li><a href="/wiki/Cistern" title="Cistern">Cistern</a></li> <li><a href="/wiki/Closet_flange" title="Closet flange">Closet flange</a></li> <li><a href="/wiki/Concentric_reducer" title="Concentric reducer">Concentric reducer</a></li> <li><a href="/wiki/Condensate_pump" title="Condensate pump">Condensate pump</a></li> <li><a href="/wiki/Coupling_(piping)" title="Coupling (piping)">Coupling (piping)</a></li> <li><a href="/wiki/Diaphragm_valve" title="Diaphragm valve">Diaphragm valve</a></li> <li><a href="/wiki/Dielectric_union" class="mw-redirect" title="Dielectric union">Dielectric union</a></li> <li><a href="/wiki/Double_check_valve" title="Double check valve">Double check valve</a></li> <li><a href="/wiki/Eccentric_reducer" title="Eccentric reducer">Eccentric reducer</a></li> <li><a href="/wiki/Expansion_tank" title="Expansion tank">Expansion tank</a></li> <li><a href="/wiki/Faucet_aerator" title="Faucet aerator">Faucet aerator</a></li> <li><a href="/wiki/Float_switch" title="Float switch">Float switch</a></li> <li><a href="/wiki/Float_valve" class="mw-redirect" title="Float valve">Float valve</a></li> <li><a href="/wiki/Floor_drain" title="Floor drain">Floor drain</a></li> <li><a href="/wiki/Flow_limiter" title="Flow limiter">Flow limiter</a></li> <li><a href="/wiki/Flushing_trough" title="Flushing trough">Flushing trough</a></li> <li><a href="/wiki/Flushometer" title="Flushometer">Flushometer</a></li> <li><a href="/wiki/Gate_valve" title="Gate valve">Gate valve</a></li> <li><a href="/wiki/Globe_valve" title="Globe valve">Globe valve</a></li> <li><a href="/wiki/Grease_trap" title="Grease trap">Grease trap</a></li> <li><a href="/wiki/Grinder_pump" title="Grinder pump">Grinder pump</a></li> <li><a href="/wiki/Hose_coupling" title="Hose coupling">Hose coupling</a></li> <li><a href="/wiki/Manifold_(fluid_mechanics)" title="Manifold (fluid mechanics)">Manifold</a></li> <li><a href="/wiki/Needle_valve" title="Needle valve">Needle valve</a></li> <li><a href="/wiki/Nipple_(plumbing)" title="Nipple (plumbing)">Nipple (plumbing)</a></li> <li><a href="/wiki/Pinch_valve" title="Pinch valve">Pinch valve</a></li> <li><a href="/wiki/Piping_and_plumbing_fitting" title="Piping and plumbing fitting">Piping and plumbing fitting</a></li> <li><a href="/wiki/Plug_(sanitation)" title="Plug (sanitation)">Plug (sanitation)</a></li> <li><a href="/wiki/Pressure_regulator" title="Pressure regulator">Pressure regulator</a></li> <li><a href="/wiki/Pressure_vacuum_breaker" title="Pressure vacuum breaker">Pressure vacuum breaker</a></li> <li><a href="/wiki/Pressure-balanced_valve" title="Pressure-balanced valve">Pressure-balanced valve</a></li> <li><a href="/wiki/Pump" title="Pump">Pump</a></li> <li><a href="/wiki/Radiator_(heating)" title="Radiator (heating)">Radiator (heating)</a></li> <li><a href="/wiki/Reduced_pressure_zone_device" title="Reduced pressure zone device">Reduced pressure zone device</a></li> <li><a href="/wiki/Reducer" class="mw-redirect" title="Reducer">Reducer</a></li> <li><a href="/wiki/Relief_valve" title="Relief valve">Relief valve</a></li> <li><a href="/wiki/Riser_clamp" title="Riser clamp">Riser clamp</a></li> <li><a href="/wiki/Rooftop_water_tower" title="Rooftop water tower">Rooftop water tower</a></li> <li><a href="/wiki/Safety_valve" title="Safety valve">Safety valve</a></li> <li><a href="/wiki/Sewage_pump" class="mw-redirect" title="Sewage pump">Sewage pump</a></li> <li><a href="/wiki/Street_elbow" title="Street elbow">Street elbow</a></li> <li><a href="/wiki/Submersible_pump" title="Submersible pump">Submersible pump</a></li> <li><a href="/wiki/Tap_(valve)" title="Tap (valve)">Tap (valve)</a></li> <li><a href="/wiki/Thermostatic_mixing_valve" title="Thermostatic mixing valve">Thermostatic mixing valve</a></li> <li><a href="/wiki/Trench_drain" title="Trench drain">Trench drain</a></li> <li><a href="/wiki/Vacuum_breaker" title="Vacuum breaker">Vacuum breaker</a></li> <li><a href="/wiki/Vacuum_ejector" title="Vacuum ejector">Vacuum ejector</a></li> <li><a href="/wiki/Valve" title="Valve">Valve</a></li> <li><a href="/wiki/Water_tank" title="Water tank">Water tank</a></li> <li><a href="/wiki/Zone_valve" title="Zone valve">Zone valve</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Plumbing_fixture" title="Plumbing fixture">Plumbing fixtures</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Accessible_bathtub" title="Accessible bathtub">Accessible bathtub</a></li> <li><a href="/wiki/Bathtub" title="Bathtub">Bathtub</a></li> <li><a href="/wiki/Bidet" title="Bidet">Bidet</a></li> <li><a href="/wiki/Dehumidifier" title="Dehumidifier">Dehumidifier</a></li> <li><a href="/wiki/Dishwasher" title="Dishwasher">Dishwasher</a></li> <li><a href="/wiki/Drinking_fountain" title="Drinking fountain">Drinking fountain</a></li> <li><a href="/wiki/Electric_water_boiler" title="Electric water boiler">Electric water boiler</a></li> <li><a href="/wiki/Evaporative_cooler" title="Evaporative cooler">Evaporative cooler</a></li> <li><a href="/wiki/Flush_toilet" title="Flush toilet">Flush toilet</a></li> <li><a href="/wiki/Garbage_disposal_unit" title="Garbage disposal unit">Garbage disposal unit</a></li> <li><a href="/wiki/Hot_water_storage_tank" title="Hot water storage tank">Hot water storage tank</a></li> <li><a href="/wiki/Humidifier" title="Humidifier">Humidifier</a></li> <li><a href="/wiki/Icemaker" title="Icemaker">Icemaker</a></li> <li><a href="/wiki/Instant_hot_water_dispenser" title="Instant hot water dispenser">Instant hot water dispenser</a></li> <li><a href="/wiki/Laundry_tub" class="mw-redirect" title="Laundry tub">Laundry tub</a></li> <li><a href="/wiki/Shower" title="Shower">Shower</a> <ul><li><a href="/wiki/Water_recycling_shower" title="Water recycling shower">water recycling shower</a></li></ul></li> <li><a href="/wiki/Sink" title="Sink">Sink</a></li> <li><a href="/wiki/Storage_water_heater" title="Storage water heater">Storage water heater</a></li> <li><a href="/wiki/Sump_pump" title="Sump pump">Sump pump</a></li> <li><a href="/wiki/Tankless_water_heater" class="mw-redirect" title="Tankless water heater">Tankless water heater</a></li> <li><a href="/wiki/Urinal" title="Urinal">Urinal</a></li> <li><a href="/wiki/Washing_machine" title="Washing machine">Washing machine</a></li> <li><a href="/wiki/Washlet" title="Washlet">Washlet</a></li> <li><a href="/wiki/Water_dispenser" title="Water dispenser">Water dispenser</a></li> <li><a href="/wiki/Water_filter" title="Water filter">Water filter</a></li> <li><a href="/wiki/Water_heater" class="mw-redirect" title="Water heater">Water heater</a></li> <li><a href="/wiki/Water_softener" class="mw-redirect" title="Water softener">Water softener</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Specialized tools</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Basin_wrench" title="Basin wrench">Basin wrench</a></li> <li><a href="/wiki/Blowtorch" title="Blowtorch">Blowtorch</a></li> <li><a href="/wiki/Borescope" title="Borescope">Borescope</a></li> <li><a href="/wiki/Core_drill" title="Core drill">Core drill</a></li> <li><a href="/wiki/Drain_cleaner" title="Drain cleaner">Drain cleaner</a></li> <li><a href="/wiki/Driving_cap" title="Driving cap">Driving cap</a></li> <li><a href="/wiki/Flare-nut_wrench" class="mw-redirect" title="Flare-nut wrench">Flare-nut wrench</a></li> <li><a href="/wiki/Pipecutter" title="Pipecutter">Pipecutter</a></li> <li><a href="/wiki/Pipe_wrench" title="Pipe wrench">Pipe wrench</a></li> <li><a href="/wiki/Plumber%27s_snake" title="Plumber's snake">Plumber's snake</a></li> <li><a href="/wiki/Plumber_wrench" title="Plumber wrench">Plumber wrench</a></li> <li><a href="/wiki/Plunger" title="Plunger">Plunger</a></li> <li><a href="/wiki/Strap_wrench" title="Strap wrench">Strap wrench</a></li> <li><a href="/wiki/Tap_and_die" title="Tap and die">Tap and die</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Measurement<br />and control</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Control_valve" title="Control valve">Control valve</a></li> <li><a href="/wiki/Flow_sensor" class="mw-redirect" title="Flow sensor">Flow sensor</a></li> <li><a href="/wiki/Pressure_sensor" class="mw-redirect" title="Pressure sensor">Pressure sensor</a></li> <li><a href="/wiki/Water_detector" title="Water detector">Water detector</a></li> <li><a href="/wiki/Water_metering" title="Water metering">Water metering</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Professions,<br />trades,<br />and services</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Hydronic_balancing" title="Hydronic balancing">Hydronic balancing</a></li> <li><a href="/wiki/Hydrostatic_testing" class="mw-redirect" title="Hydrostatic testing">Hydrostatic testing</a></li> <li><a href="/wiki/Leak_detection" title="Leak detection">Leak detection</a></li> <li><a href="/wiki/Mechanical,_electrical,_and_plumbing" title="Mechanical, electrical, and plumbing">Mechanical, electrical, and plumbing</a></li> <li><a href="/wiki/Pipe_marking" title="Pipe marking">Pipe marking</a></li> <li><a href="/wiki/Pipefitter" title="Pipefitter">Pipefitter</a></li> <li><a href="/wiki/Pipelayer" title="Pipelayer">Pipelayer</a></li> <li><a href="/wiki/Plumber" title="Plumber">Plumber</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Industry <br />organizations <br />and standards</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/International_Association_of_Plumbing_and_Mechanical_Officials" class="mw-redirect" title="International Association of Plumbing and Mechanical Officials">International Association of Plumbing and Mechanical Officials (IAPMO)</a></li> <li><a href="/wiki/NSF_International" title="NSF International">NSF International</a></li> <li><a href="/wiki/Plumbing_%26_Drainage_Institute" title="Plumbing & Drainage Institute">Plumbing & Drainage Institute (PDI)</a></li> <li><a href="/wiki/Uniform_Plumbing_Code" title="Uniform Plumbing Code">Uniform Plumbing Code (UPC)</a></li> <li><a href="/wiki/World_Plumbing_Council" title="World Plumbing Council">World Plumbing Council (WPC)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Health and safety</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Plumbing_code" title="Plumbing code">Plumbing code</a></li> <li><a href="/wiki/Scalding" title="Scalding">Scalding</a></li> <li><a href="/wiki/Waterborne_disease" title="Waterborne disease">Waterborne disease</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">See also</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0;text-align: middle;"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Fire_sprinkler_system" title="Fire sprinkler system">Fire sprinkler system</a></li> <li><a href="/wiki/Piping" title="Piping">Piping</a></li> <li><a href="/wiki/Template:HVAC" title="Template:HVAC">Template:HVAC</a></li> <li><a href="/wiki/Template:Public_health" title="Template:Public health">Template:Public health</a></li> <li><a href="/wiki/Template:Sewerage" title="Template:Sewerage">Template:Sewerage</a></li> <li><a href="/wiki/Template:Toilets" class="mw-redirect" title="Template:Toilets">Template:Toilets</a></li> <li><a href="/wiki/Template:Wastewater" title="Template:Wastewater">Template:Wastewater</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Backflow_prevention_device&oldid=1213233933">https://en.wikipedia.org/w/index.php?title=Backflow_prevention_device&oldid=1213233933</a>"</div></div> <div id="catlinks" class="catlinks" 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