Think of it as your building's annual physical — except the law actually requires this one.
Normally, clean water flows one direction — from the city main into your building. But when pressure drops or reverses (a water-main break, a hydrant opening, a pump kicking on), water can get pulled backward. If that backward flow carries irrigation runoff, fire-system water, or chemicals into the public supply, it's a contamination risk for everyone on the line.
A backflow prevention assembly is a one-way gate that keeps contaminated water from ever flowing back. But it has internal parts — checks, springs, relief valves — that wear out silently. The only way to know it still works is to test it. That's why California Title 17 and your local water purveyor require a certified test every year.
Miss the annual deadline and your water district will notice. Typically you'll get a reminder, then a more pointed notice, then — for stubborn cases — fees or even a water-service shutoff until you're compliant. None of it is dramatic if you stay ahead of it, which is the entire point of getting matched with a tester who tracks the date for you.
Get matched with a certified tester who handles the test and the filing — every year.
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