Annual backflow testing in Colorado: what property owners actually have to do
August 28, 2026 · Domana
Backflow prevention is one of those requirements that sits quietly in the background until a letter arrives. It applies to more properties than most owners expect, the testing window is annual, and the consequence of missing it can be water service shutoff.
What a backflow preventer does
A backflow prevention assembly stops water from reversing direction and re-entering the public supply. That reversal happens when pressure drops in the main — a hydrant opens, a line breaks — and water in your building’s system gets pulled backward. If that water has passed through an irrigation system, a boiler, or a fire suppression line, it carries whatever it picked up along the way.
Who it applies to
Any property with a cross-connection between the potable supply and a system that could contaminate it. In practice, that means:
- Irrigation and sprinkler systems
- Fire suppression systems
- Boilers and closed-loop heating
- Pools and spas
- Commercial kitchens with certain equipment
Most Colorado water providers require an assembly on any of these, and every assembly requires annual testing.
The testing requirement
Testing must be performed by a certified backflow assembly tester, and results are filed with your water provider. The interval is annual. Providers typically send a notice, but the obligation sits with the property owner regardless of whether the notice arrives or reaches the right person.
What happens when it lapses
Providers escalate on their own schedules, but the pattern is consistent: a reminder, then a warning, then a shutoff notice. Water service termination is a real outcome, and it arrives faster on commercial accounts than most owners expect.
The practical problem
The requirement itself is simple. Missing it is almost always an administrative failure rather than a technical one — the tester came last March, nobody wrote down which March, the person who handled it changed jobs, and the notice went to an address that is no longer monitored.
That’s a records problem, and it’s the reason it keeps happening at properties that have every intention of complying. The assembly doesn’t know when it was last tested. Someone has to.
Domana tracks compliance intervals against the specific equipment they apply to, so the date surfaces before the notice does. See how it works.