Academy/Utilities & Infrastructure
Backflow prevention
Keeping contaminated water out of the drinking water your residents use every day.
A cross-connection is any actual or potential link between a drinking water system and a source of contamination, such as an irrigation line, pool fill, or fire sprinkler tied into the water supply. A backflow preventer stops water flowing backward through that link. Testing frequency and who is responsible are set locally, not nationally.
What a cross-connection actually is
Most HOAs have several cross-connections without anyone naming them that. An irrigation system tied into the domestic water line, a pool that refills from a hose bib, a fire sprinkler riser, and a boiler feed line are all points where non-potable or stagnant water could flow backward into the drinking water supply if pressure drops.
"This is any actual or potential connection between public water and a contaminated source."
Source: Distribution Resources for Small Drinking Water Systems, U.S. Environmental Protection Agency
A backflow preventer is the mechanical device installed at these points to keep water flowing the right direction. Where your association has one, and whether it is working, is worth knowing before a health department inspector asks.
Where the association's responsibility begins and ends
Water utilities commonly draw a line at the meter: the utility is responsible for cross-connection control up to that point, and the property owner is responsible from the meter onward. In Washington state, for example, that line is set by regulation.
"The purveyor's responsibility for cross-connection control shall begin at the water supply source... and end at the point of delivery to the consumer's water system, which begins at the downstream end of the service connection or water meter."
Source: WAC 246-290-490, Washington State Department of Health
This meter-based split is a common pattern, but the exact device required, its hazard rating, and installation rules on your side of that line come from your own state's plumbing code and your local water utility. Do not assume Washington's rule, or any other state's, applies where you are.
Testing and device rules are set locally, not nationally
How often a backflow preventer must be tested, and by whom, is set by the water utility serving the property and by the state plumbing code it operates under. One municipal utility requires annual testing:
"Backflow prevention assemblies are required to be tested annually per State Plumbing Code and Drinking Water regulations and submitted to the water supplier."
Source: Cross Connection Control and Backflow Prevention, Salt Lake City Public Utilities
Annual testing is common, but it is not a universal rule, so confirm the interval directly with your water provider. For building a cross-connection control program, the industry reference is the American Water Works Association's Manual M14, Backflow Prevention and Cross-Connection Control; consult it, or a licensed backflow tester, rather than guessing at a device type or schedule.
Check yourself
Answer before you read the explanation, recalling it is what makes it stick.
Your community's irrigation system ties into the same pipe that supplies drinking water to homes. What is this connection called?
The board wants to know how often the clubhouse's backflow preventer must be tested. Where should the board look first?
In Washington state, where does the water utility's cross-connection responsibility end and the property owner's begin?
Sources
- Distribution Resources for Small Drinking Water Systems, U.S. Environmental Protection Agency
- WAC 246-290-490, cross-connection control, Washington State Department of Health
- Cross Connection Control and Backflow Prevention, Salt Lake City Public Utilities
- Manual M14, Backflow Prevention and Cross-Connection Control, American Water Works Association
Related elsewhere in the Academy
Utilities & Infrastructure
Next, learn how your association's private water system fits into state and federal oversight in Private utility systems.
Which point divides the utility's cross-connection responsibility from the association's, and how often and by what device backflow must be tested, vary by state plumbing code and by the water utility serving your property.