Cross‑Connection Control and Backflow Prevention Program

The Colorado Department of Public Health and Environment (CDPHE) regulates drinking water quality under the Colorado Primary Drinking Water Regulations (Regulation 11). These regulations establish the minimum standards for cross‑connection control and backflow prevention that Willows Water enforces within its system. To support consistent implementation of Regulation 11, CDPHE has issued Policy 7, which provides guidance and clarification on cross‑connection control requirements for public water systems.

Willows Water’s Cross‑Connection Control and Backflow Prevention Program protects the public drinking water supply from potential pollution or contamination that could, under certain circumstances, be introduced from private properties into the public water system. 

In addition to installation, customers must ensure that backflow prevention assemblies are:

  • Tested at the time of installation, and
  • Tested annually thereafter

Willows Water offers backflow testing services for customer convenience:

  • Backflow Test – Standard: $85
  • Backflow Test – Confined Space: $100

Customers may also use a certified third‑party backflow prevention assembly tester. All third‑party test results must meet the following requirements:

  • Passing test reports must be submitted within 10 business days of the test date. Reports received after this timeframe will be rejected.
  • Failed test results must be reported within 24 hours of testing.

Failure to submit required test results within the specified timeframes may result in enforcement action or interruption of water service.

All backflow test reports—both passing and failed—must be emailed to: backflows@willowswater.org

Who Is Required to Have Backflow Prevention 

The following services are required to install and maintain approved backflow prevention assemblies:

  • Commercial and industrial services
  • Domestic services where site‑specific hazards exist
  • Irrigation services
  • Fire line services
  • Customers with an auxiliary water supply (e.g., wells or ponds)
  • Multi‑family properties which three or more seperate living units are supplies water. 

Requirements for single‑family residential properties are determined based on site‑specific hazard assessments.

There are no exemptions or grandfathering of backflow prevention requirements.

What is a Cross Connection 

A cross‑connection is any actual or potential connection between the public drinking water system and another source that could introduce contaminants into the public system.

To prevent cross‑connections, approved backflow prevention assemblies are required at certain service connections depending on site conditions and potential hazards.

Why Backflow Prevention Is Important 

Backflow is the unwanted reversal of water flow, allowing water or other substances—such as chemicals, fertilizers, or contaminants—to enter the public drinking water supply.

There are two primary ways backflow can occur:

Backsiphonage

Backsiphonage happens when there is a sudden drop in water pressure in the public distribution system, causing water from a private system to be drawn back into the public supply. This may occur during events such as a water main break or large firefighting operations.

Backpressure

Backpressure occurs when pressure in a private plumbing system exceeds the pressure in the public water system, forcing water to flow backward. This can be caused by pumps, elevation changes within a building, or pressurized systems.

According to the U.S. Environmental Protection Agency, cross‑connections without proper protection can pose a serious public health risk and have been documented as causes of drinking water contamination and illness.

Types of Backflow Prevention Assemblies 

Backflow prevention assemblies installed within the Willows Water distribution system must be approved by the University of Southern California’s Foundation for Cross-Connection Control and Hydraulic Research, otherwise known as being USC-approved.

Reduced Pressure Principle Assembly (RP)

An RP assembly is required for most commercial, industrial, and some multi‑family applications. RPs may also be used for irrigation systems when a pressure vacuum breaker cannot be installed.

Installation Requirements:

  • Minimum 12 inches off the floor and 12 inches from a wall
  • A platform is required if installed over 5 feet high
  • Adequate drainage must be provided
  • Must be protected from freezing

Double Check Valve Assembly (DC)

A DC assembly is required for fire lines without antifreeze or chemical additives and some residential applications.
DC assemblies are not permitted on irrigation systems.

Installation Requirements:

  • Minimum 12 inches off the floor and 12 inches from a wall
  • A platform is required if installed over 5 feet high

Pressure Vacuum Breaker (PVB)

PVBs are used for irrigation systems only and have specific installation limitations.

Installation Requirements:

  • Must be installed at least 12 inches above the highest point of use
  • Minimum 12 inches from a wall
  • Cannot be subjected to continuous backpressure

Atmospheric Vacuum Breaker (AVB)

AVBs are point‑of‑use devices for specific internal plumbing processes.
AVBs are not allowed for irrigation or containment purposes.

Irrigation systems must be protected with either:

  • A Reduced Pressure (RP) assembly, or
  • A Pressure Vacuum Breaker (PVB), depending on site conditions.