Backflow Laws: Colorado
Colorado Backflow Prevention Laws, Regulations, and Compliance Requirements
Colorado's backflow prevention requirements are governed by the Colorado Primary Drinking Water Regulations — specifically Regulation 11, Section 11.39 — administered by the Colorado Department of Public Health and Environment (CDPHE). Regulation 11 was updated in August 2020 with further policy refinements in 2021 and rule amendments in 2023. This guide covers Colorado's state framework, the annual report requirement, Denver Water's 60-day compliance window, BSI Online's role across suburban utilities, and requirements across Colorado's major water systems.
Colorado State Regulatory Framework
Colorado’s cross-connection control requirements are contained in the Colorado Primary Drinking Water Regulations at Regulation 11, Section 11.39 — the Backflow Prevention and Cross-Connection Control (BPCCC) Rule — administered by the Colorado Department of Public Health and Environment (CDPHE) Water Quality Control Division. CDPHE holds EPA primacy under the federal Safe Drinking Water Act.
Since the mid-1980s, CDPHE has mandated that all water districts in Colorado implement a cross-connection control program on their potable water systems. Starting in 2020, water districts must also enforce compliance and report results back to CDPHE. The 2020 rulemaking made significant changes to Section 11.39 and established new requirements for storage tank maintenance and the BPCCC rule. CDPHE’s Water Quality Control Commission voted unanimously on further BPCCC rule updates on August 14, 2023, which became effective in late 2023.
Key Regulation 11 BPCCC requirements include: a written cross-connection control plan for each public water system; regular surveys of all non-single-family residential service connections (commercial, industrial, multi-family, irrigation, fire lines); annual testing of all required backflow prevention assemblies; and submission of an annual backflow report to CDPHE. CDPHE provides templates for the written backflow program, example ordinances, backflow survey questionnaires, and the annual report and tracking template as guidance documents on its BPCCC page.
Colorado's Annual Reporting Requirement
Colorado is classified as a high-regulation state nationally in part because of its annual reporting requirement: water systems must submit an annual backflow report to CDPHE covering the preceding calendar year. This report documents cross-connection survey activities, the inventory of backflow assemblies in the system, testing compliance status, and enforcement actions taken during the year. Annual reporting creates accountability at the state level and ensures CDPHE can track program effectiveness statewide.
Tester Certification in Colorado
Colorado accepts certifications from both ABPA (American Backflow Prevention Association) and ASSE (American Society of Sanitary Engineering) for standard domestic and irrigation backflow assembly testing. In 2025, the Colorado General Assembly passed HB25-1077, which clarified that plumbing licensure is not required to inspect, test, and repair backflow assemblies — certified testers holding ABPA or ASSE certification can perform testing and repair without a plumbing license for domestic and irrigation assemblies. However, fire suppression system backflow assemblies require an additional certification: the State of Colorado Fire Suppression System Contractor-Backflow credential, which is required before Denver Water (and most other utilities) will accept fire assembly test results.
All approved backflow prevention assemblies must be listed by USC-FCCCHR (University of Southern California Foundation for Cross-Connection Control and Hydraulic Research) and must be confirmed approved in the specific installation orientation (horizontal, vertical, etc.).
Because certification is locally administered, a tester approved by Birmingham Water Works Board may need separate approval to file test reports with Central Alabama Water or Auburn Water Resource Management. Contractors working across multiple Alabama service areas should confirm their approval status with each water purveyor before performing tests in that purveyor’s service territory.
HB25-1077: Colorado's 2025 Tester Authorization Clarification
Colorado HB25-1077, passed in 2025, clarified that certified backflow assembly testers do not need a plumbing license to test, inspect, and repair domestic and irrigation backflow assemblies. This resolves longstanding ambiguity about the role of plumbing licensure in backflow work. Fire suppression system assemblies still require the separate State Fire Suppression System Contractor-Backflow certification. Confirm with your specific water utility whether they have adopted any additional requirements beyond the state standard.
Major Water Purveyors in Colorado
Denver Water
Denver Water is Colorado’s largest water utility, serving approximately 1.5 million people in Denver and surrounding suburbs. Denver Water operates one of the most structured cross-connection control programs in the state, aligned with CDPHE Regulation 11.39(3)(c)(i). Annual testing is required for all covered assemblies — Denver Water requires testing within 60 days of the annual due date. Denver Water sends a testing reminder notice 30 days before the annual test is due.
Critically, Denver Water requires that initial post-installation testing be completed by a certified ABPA or ASSE tester within 48 hours of installation. All test reports must be sent directly to Denver Water’s Cross-Connection Control office at crossconnectioncontrol@denverwater.org. The Cross-Connection Control team can be reached at 303-628-5969.
Denver Water conducts Cross-Connection Control Surveys of existing properties to identify unprotected cross-connections. If an unprotected cross-connection is discovered during a survey, the property owner has 60 days to install an approved assembly — or contact the Cross-Connection Control office for approval of an extended period if the installation requires more time. Denver Water has implemented a $250 penalty (effective May 1, 2025) assessed after three mailed notification letters have gone unanswered and the service enters suspension status. This penalty is non-refundable.
Denver Water requires USC-approved assemblies only. For fire suppression assemblies, the tester must hold the Colorado Fire Suppression System Contractor-Backflow credential in addition to ABPA or ASSE certification.
Aurora Water
Aurora Water serves the City of Aurora and surrounding areas east of Denver. Aurora’s cross-connection control program is aligned with Regulation 11.39 requirements. Annual testing by ABPA or ASSE-certified testers is required. Test reports are filed directly with Aurora Water’s cross-connection control department.
Colorado Springs Utilities
Colorado Springs Utilities serves El Paso County. The utility operates a comprehensive cross-connection control program under Regulation 11.39, requiring annual testing for all commercial, industrial, multi-family, irrigation, and fire line services. Single-family residential services are not included unless a specific hazard is identified.
Suburban Denver Utilities Using BSI Online
Many suburban Denver-area water districts — including the Town of Johnstown, Parker Water and Sanitation District (PWSD), East Larimer County Water District (ELCO), and Cherry Creek Valley Water and Sanitation District — use BSI Online as their third-party program administrator. Testing results for properties in these utilities must be submitted to BSI Online rather than directly to the utility. Cherry Creek Valley specifies that irrigation backflow annual tests must be submitted by May 31st each year. Parker Water accepts only ABPA or ASSE-certified testers with current test kit calibration documentation.
Fort Collins Utilities, Boulder Water, and Northern Colorado
Fort Collins Utilities, the City of Boulder Water Resources, and other Front Range utilities each operate individual cross-connection control programs aligned with Regulation 11.39. Annual testing requirements apply uniformly. Each utility should be contacted directly for their specific reporting platforms, approved tester lists, and deadline calendars.
Single-Family Residential Is Generally Exempt in Colorado
Colorado’s Regulation 11 targets non-single-family residential services — commercial, industrial, multi-family, irrigation service lines, and fire lines are all subject to mandatory backflow prevention and annual testing. Single-family residences are generally not part of utility cross-connection control programs unless a specific hazard is identified (such as an auxiliary water supply like a well or pond). However, single-family homes with in-ground irrigation systems or other auxiliary supplies should confirm their specific status with their water utility, as individual utilities may apply broader requirements than the state baseline.
Property Owner Compliance Summary for Colorado
Testing: Annual testing by ABPA or ASSE-certified testers. Fire assemblies require the additional Colorado Fire Suppression Contractor-Backflow credential.
Filing: To your specific utility (Denver Water: crossconnectioncontrol@denverwater.org). Many suburban utilities use BSI Online.
Survey response: Respond promptly to Denver Water or utility cross-connection surveys. Unprotected connections must be resolved within 60 days typically.
Annual report: Your water utility is responsible for the annual CDPHE report, but your compliance data feeds into it.
Records: Retain test and repair records per your utility’s requirements.
Find a Certified Backflow Tester in Colorado
Find ABPA or ASSE-certified, utility-approved testers at getyourbackflowtested.com/backflow-testing-near-me/colorado-backflow-testing — covering Denver, Aurora, Colorado Springs, Fort Collins, and suburban Denver markets.
Colorado Regulatory Reference Links
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CDPHE — Backflow Prevention and Cross-Connection Control (BPCCC) |
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Regulation 11, Section 11.39 — BPCCC Rule |
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CDPHE — 2023 BPCCC Rule Rulemaking History |
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Denver Water — Cross-Connection Control Program |
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Denver Water — Cross-Connection Control Survey |
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Parker Water and Sanitation District — Backflow Program |
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East Larimer County Water District — BPCCC Program |
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Cherry Creek Valley W&SD — Backflow Program |