Uncontrolled Cross-Connections

The purpose of this document is to help the public define and categorize domestic water connections that are considered “uncontrolled cross-connections” within the public water distribution system. An uncontrolled cross-connection presents a significant risk to the integrity of the potable water supply by allowing potential backflow of contaminants or pollutants. The control of cross-connections is a critical component of backflow prevention and is required under Colorado’s Safe Drinking Water Program Policy Number DW-007: Backflow Prevention and Cross-Connection Control and Regulation 11.

Uncontrolled cross-connections are those in which a properly installed, maintained, and tested backflow prevention assembly or method is not present, or is not functioning as intended. The following subsections identify the specific conditions under which a cross-connection is considered uncontrolled.

1. Absence of a Backflow Prevention Assembly or Method

Any identified cross-connection where no approved backflow prevention assembly or method has been installed shall be classified as uncontrolled.

2. Inadequate Type of Assembly or Method Installed

A cross-connection protected by an assembly or method that does not provide adequate protection for the degree of hazard identified shall be deemed uncontrolled.

Examples include:

• Installation of a double check valve assembly (DC) in a system utilizing chemicals. Where chemicals are present, a reduced pressure principle (RP) assembly or an air gap is required.
• Installation of a pressure vacuum breaker (PVB) at a connection subject to back pressure conditions.

3. Improper Installation of Assembly or Method

A cross-connection where a backflow prevention assembly or method has been installed in a manner inconsistent with the manufacturer’s approval or specifications shall be classified as uncontrolled.

Examples include:

• Improper orientation: Installing an assembly vertically when it is approved only for horizontal installation.
• Improper location: Installing an RP assembly in a pit or vault without adequate drainage, resulting in potential submersion.

4. Assemblies That Have Failed Testing

Any backflow prevention assembly that fails a required performance test shall be considered uncontrolled until it has been repaired and successfully retested.
While test failures may occur, an assembly in a failed state does not provide adequate protection and, therefore, constitutes an uncontrolled cross-connection.

5. Assemblies or Methods Not Tested or Inspected Within the Previous Two Calendar Years

Backflow prevention assemblies and methods installed to protect the public water supply must be tested or inspected annually.
If an assembly or method has not been tested or inspected within the preceding two calendar years, it shall be classified as uncontrolled.

Extensions beyond this two-year interval (e.g., 120 days) are not permitted. Any assembly or method that remains untested or uninspected after two years constitutes a treatment technique violation and requires issuance of a Tier 2 Public Notice in accordance with Regulation 11.

Compliance Requirements

All uncontrolled cross-connections must be corrected, replaced, repaired, or properly protected within the timeframe specified by the water supplier or regulatory authority, typically not to exceed 30 days from the date of identification. Failure to correct an uncontrolled cross-connection within the specified period constitutes a violation of this policy and may result in enforcement actions, including termination of water service or issuance of a public notice, as required by Regulation 11.