City water utility · Colorado
Backflow testing in Denver, CO
Denver Water's rules: who must test, when it's due, testers, filing and penalties.
Businesses, irrigation lines, fire lines and homes with a well or other hazard must test backflow assemblies when installed and every year after. Reports go to Denver Water by email on its form. After three unanswered notices, service is suspended and a $250 penalty is billed.
- Who
- Businesses: every year
- Lawn sprinkler systems: every year
- Fire sprinkler lines: every year
- Apartments and condos: every year (some)
- Homes (other than sprinklers): every year (some)
- Other connections: every year
- Due
- Have each assembly tested once a year.
- Testers
- Hire a backflow tester certified by ABPA (American Backflow Prevention Association) or ASSE.
- Filing
- You or your tester files by email. No filing fee listed.
- If late
- Water can be shut off. Penalty when service is suspended after three unanswered letters: $250.
Who must have a backflow test
Businesses, dedicated irrigation lines and fire lines must have an approved backflow assembly. Apartments and homes need one only when there is a hazard, such as a well, a pond or a fire sprinkler system. Have a new assembly tested within 48 hours of installing it, then every year.
- BusinessesRequiredupon installation and every year after
High-hazard sites need a reduced pressure (RP) assembly. Low-hazard sites may use a double check (DC) if Denver Water approves it.
- Lawn sprinkler systemsRequiredevery year, as the water is turned on
Applies to dedicated irrigation lines. The testing season runs May to September. Use an RP or a pressure vacuum breaker (PVB); double checks and atmospheric vacuum breakers are not allowed.
- Fire sprinkler linesRequiredevery year
Fire lines without antifreeze or chemical additives use a double check (DC). The tester needs an extra state certification for fire backflow work.
- Apartments and condosSomeevery year
Required when Denver Water finds a hazard on the site. Some buildings need an RP assembly.
- Homes (other than sprinklers)Someupon installation and every year after
Most single-family homes are exempt. Homes with a fire sprinkler system, a well or pond, or another known hazard must test. A home with a well or pond also needs a Dual Water Supply Agreement with Denver Water.
- Other connectionsRequiredevery year
Any property with a well, pond or other second water supply must have a tested assembly. Recycled water lines are tested too where an assembly is required.
Assemblies tested: Reduced pressure assembly (RP or RPZ), Double check valve assembly, Pressure vacuum breaker. What these are
Source: denverwater.org · checked Oct 18, 2026
When the test is due
Have each assembly tested once a year. Irrigation assemblies are tested when the water is turned on for the season, between May and September. A new assembly must be tested within 48 hours of being installed.
Notices: Denver Water sends a reminder 30 days before the yearly test is due. If the test is not done, three letters go out over 60 days to the service address and to the backflow contact on file before service is suspended. If you get no letters, call Customer Care to update the backflow contact's mailing address.
Source: denverwater.org · checked Oct 18, 2026
Finding a tester
Hire a backflow tester certified by ABPA (American Backflow Prevention Association) or ASSE. A plumbing license is not needed to test or repair an assembly. For fire sprinkler assemblies, the tester must also hold the State of Colorado Fire Suppression System Contractor-Backflow certification.
Denver Water does not test assemblies itself; you hire a tester.
Source: denverwater.org · checked Oct 18, 2026
Filing the test report
- Who files
- You or your tester
- How
- By email
- Deadline
- Within 5 days after the test
- Fee
- None listed by the utility
- Form
- Test report form
Source: denverwater.org · checked Oct 18, 2026
If the test is late or fails
If the yearly test is not done, Denver Water mails three letters over 60 days. If no one responds, water service is suspended and a $250 penalty goes on the bill, with no refund. Tell the Cross-Connection Control office about any delay before that happens. A noncompliance turn-off fee and a turn-on fee may also apply.
- Penalty when service is suspended after three unanswered letters: $250
- Noncompliance turn-off fee: $36
- Turn-on fee when service is restored: $36
Failed test: If an assembly fails its test, have it repaired and tested again within 15 days.
Rule: Denver Water Operating Rules § 11.03.2
Source: denverwater.org · checked Oct 18, 2026
For testers working in Denver
- ABPA or ASSE backflow tester certification
- State of Colorado Fire Suppression System Contractor-Backflow certification for fire assemblies
- Copy of ABPA or ASSE certification sent to Cross Connection Control at each renewal
- Test kit calibration certification sent every year
- Dedicated recycled water test gauge
- Test reports on Denver Water's test form
Send a copy of your ABPA or ASSE certification to Denver Water's Cross Connection Control group each time you renew it, and send your test kit calibration certificate every year. Fill out Denver Water's own test form and send each report within 5 days of the test. If an assembly fails and can't be fixed that day, tell Cross Connection Control within 24 hours and send the failed report within 3 days.
Source: denverwater.org · checked Oct 18, 2026
The rules behind it
- Colorado Primary Drinking Water Regulations (Regulation 11), section 11.39: State cross-connection rule. Denver Water cites 11.39(3)(c)(i) for yearly testing and 11.39 for site surveys.
- Denver Water Operating Rules, Chapter 11 (Cross-Connections): 11.03.1 requires an approved assembly tested every year; 11.03.2 allows suspension of service. Effective August 28, 2025.
- Denver Water Engineering Standards, 17th Edition (2026), section 5.05: Tester duties, report timing and failed-test steps.
- CDPHE Safe Drinking Water Program Policy DW-007, Backflow Prevention and Cross-connection Control: State policy linked from the program page. Effective October 1, 2023.
- Colorado HB25-1077: Lets certified backflow testers test, inspect and repair assemblies without a plumbing license.
Contact Denver Water
- Program
- Cross-Connection Control and Backflow Prevention Program
- Phone
- 303-628-5969
- crossconnectioncontrol@denverwater.org
Source: denverwater.org · checked Oct 18, 2026
Backflow testing in Denver: questions
Do I need a backflow test for my sprinkler system in Denver?
Yes. Denver Water requires backflow assemblies on lawn sprinkler systems to be tested every year, as the water is turned on. Applies to dedicated irrigation lines. The testing season runs May to September. Use an RP or a pressure vacuum breaker (PVB); double checks and atmospheric vacuum breakers are not allowed.
When is my backflow test due in Denver?
Have each assembly tested once a year. Irrigation assemblies are tested when the water is turned on for the season, between May and September. A new assembly must be tested within 48 hours of being installed. Denver Water sends a reminder 30 days before the yearly test is due. If the test is not done, three letters go out over 60 days to the service address and to the backflow contact on file before service is suspended. If you get no letters, call Customer Care to update the backflow contact's mailing address.
How do I find a backflow tester in Denver?
Hire a backflow tester certified by ABPA (American Backflow Prevention Association) or ASSE. A plumbing license is not needed to test or repair an assembly. For fire sprinkler assemblies, the tester must also hold the State of Colorado Fire Suppression System Contractor-Backflow certification.
Who sends the backflow test report to Denver Water?
You or your tester can file the test report, within 5 days.
What happens if I skip my backflow test in Denver?
If the yearly test is not done, Denver Water mails three letters over 60 days. If no one responds, water service is suspended and a $250 penalty goes on the bill, with no refund. Tell the Cross-Connection Control office about any delay before that happens. A noncompliance turn-off fee and a turn-on fee may also apply.
What if my backflow assembly fails the test?
If an assembly fails its test, have it repaired and tested again within 15 days.
Every fact on this page comes from Denver Water's own pages, forms or code, checked Oct 18, 2026. Rules change: your notice and the utility have the final word. Spot a mistake? Tell us.