Your sprinklers are why you got the letter
For most Colorado homeowners, the backflow letter traces to one thing: the lawn irrigation system. Denver Water’s program scope names irrigation services explicitly among the connections that require an approved backflow assembly (Denver Water program page) — and the same pattern holds across Front Range districts, because the state’s Regulation 11 makes every district run a program (CDPHE BPCCC).
Why sprinklers, specifically
An irrigation system is a textbook cross-connection: pipes that sit in fertilized, pet-frequented soil, connected to the same line that feeds your kitchen tap. When street pressure drops — a main break, a hydrant draw — water can siphon backwards. The backflow assembly (usually a pressure vacuum breaker or reduced-pressure assembly near where the irrigation line leaves the house) is the one-way gate that stops that.
The annual rhythm that keeps it painless
- Spring startup: the natural moment to test. The system is being pressurized anyway, and many testers bundle startup + test in one visit. Along the Front Range this is the busy season — book early.
- The letter’s clock: districts send notices on their own schedules, keyed to when your assembly’s last passing test was filed. This year’s test starts next year’s clock; test in spring and the letter stops being scary.
- Winterization note: blowing out the system doesn’t test the assembly, and a test doesn’t winterize the system. Two jobs — many outfits do both, but confirm the test report gets FILED with your district (where reports go).
Wells and ponds count double
If your irrigation draws from a well, a pond, or any auxiliary source that also connects to district water, the district requires backflow protection for that too — auxiliary supplies are named in Denver Water’s scope. Well owners: the well side has its own world of rules at closing time — our sibling site Well Test Colorado covers it.
What the test visit looks like
A certified tester isolates the assembly, checks its check valves and relief valve against gauge readings, records the numbers on your district’s form, and files it where your district requires. Fifteen to thirty minutes for a typical residential assembly, plus the paperwork. Use the form and we’ll connect you with a certified tester who knows your district’s filing process.