Colorado · statewide
Backflow testing in Colorado: Regulation 11 and certified technicians
Updated · Prepared by the Plumb Right Now editorial team
Signs Colorado homeowners call about: A test notice from your water provider, a failed test, a dripping assembly
Short answer
Colorado's backflow and cross-connection rule is section 11.39 of the state's Primary Drinking Water Regulation (Regulation 11). Each public water supplier runs a written cross-connection control program under it. Backflow prevention assemblies are tested every year by a technician certified by the American Backflow Prevention Association (ABPA) or the American Society of Sanitary Engineering (ASSE), and the test report lists the certification number and expiration.
What Colorado requires or changes
Colorado's Backflow Prevention and Cross-Connection Control Rule is section 11.39 of the Colorado Primary Drinking Water Regulation (Regulation 11), and water suppliers must keep a written control program. [1]
Commercial, industrial, multi-family and some single-family properties must have backflow prevention assemblies installed, tested and maintained annually. [2]
Assemblies must be tested by a certified backflow technician holding current certification from the American Backflow Prevention Association or the American Society of Sanitary Engineering. [2]
Test reports must include the technician's certification number and its expiration date, or a statement that the certification is current. [2]
Which Colorado homes are affected
Single-family homes usually come into the program through lawn irrigation, a fire sprinkler line or a boiler. Your water supplier decides which connections need an assembly and sends the annual notice. See Denver and Colorado Springs for two local programs and backflow testing for how the test works.
Colorado winters and backflow assemblies
Outdoor assemblies on sprinkler systems crack when water freezes in them. Drain or remove them before the first hard freeze and have them tested when the system is turned back on in spring; a cracked body or bonnet is a common spring repair. See outdoor faucet and hose bib repair for related freeze damage.
Common questions
What Colorado rule covers backflow prevention?
Section 11.39 of Regulation 11, the Colorado Primary Drinking Water Regulation.
How often are backflow assemblies tested in Colorado?
Annually under water suppliers' Regulation 11 programs, with the report sent to the supplier.
Who can test a backflow assembly in Colorado?
A technician with current ABPA or ASSE backflow certification.
What must a Colorado backflow test report show?
The tester's certification number and expiration date, or a statement that it's current.
Why would a Colorado house have a backflow assembly at all?
Usually because of a lawn irrigation system, fire sprinklers or a boiler; the water supplier decides which connections need one.
Who runs the backflow program for my Colorado home?
Your public water supplier, under a written cross-connection control program.
Should I winterize my sprinkler backflow preventer in Colorado?
Yes. Drain or remove it before freezing weather; frozen assemblies crack.
Does a repaired Colorado backflow assembly need a new test?
Suppliers generally require a passing test after repair; check with yours.
Is backflow testing a state or city requirement in Colorado?
Both: the state rule sets the framework and each water supplier runs its own program.
Why does Colorado require backflow assemblies?
To keep irrigation water, chemicals and other contaminants from being drawn back into public drinking water.
Backflow Testing across Colorado
- Backflow Testing in DenverDenver Water's backflow rules: annual testing, the May–September irrigation season, required device types, reminders, and where results go.
- Backflow Testing in Colorado SpringsColorado Springs Utilities backflow rules: who must test annually, the July 1 deadline, the $405 fine, licensed testers entering results, and single-family guidance.
- Backflow Testing: the full guideWhat backflow is, which homes and businesses need backflow preventers, how annual backflow testing works, and what happens if a device fails.
- Plumbing in ColoradoColorado's plumbing code, licensing, climate and the cities we cover.
The same service in other states
- Backflow testing in California: the state cross-connection rulesCalifornia backflow testing under the State Water Board's cross-connection handbook: in effect since July 2024, annual tests, and what homes need.
- Backflow testing in Texas: TCEQ licensing and the annual testBackflow testing in Texas: the TCEQ tester license anyone testing or repairing assemblies must hold, test-at-install and annual rules, and gauge accuracy checks.
- Backflow testing in Washington: the annual test and certified testersWashington's cross-connection rule: assemblies tested at installation, after repair or relocation and every year, by a state-certified Backflow Assembly Tester.
- Backflow testing in Oregon: OHA-certified testersWho can test backflow assemblies in Oregon: Oregon Health Authority tester certification, the 5-day course, the 2-year cycle and the CCB license for paid work.
Sources (2)
- Town of Estes Park, Cross-Connection Control / Backflow Prevention · checked 2026-10-06
- Little Thompson Water District, Cross Connection & Backflow Prevention · checked 2026-10-06