Cross Connection / Backflow

Protect your drinking water from cross-contamination

Drinking water systems may become polluted or contaminated through uncontrolled cross connections. Water normally flows in one direction, from the public water system through the customer’s plumbing to a sink tap or other plumbing fixture. Under certain conditions water can flow in the reverse direction. 

This backsiphonage may occur due to a loss of pressure in the water distribution system during a high withdrawal of water for fire protection, a water main or plumbing system break, or a shutdown of a water main or plumbing system for repair. 

Most plumbing fixtures have a built-in backflow protection such as a physical air gap. Others, such as irrigation systems and fire suppression systems, require a mechanical backflow prevention device. The pressure vacuum breaker (PDF) or reduced pressure assembly (PDF) are two examples of the most common backflow prevention assemblies used in homes. While these systems, along with the water line coming into your home should have a backflow prevention device, care should be taken to ensure cross-contamination does not take place.

How to prevent contamination of your drinking water

  1. Do not submerge hoses - especially when filling pools, spas, ponds or other areas that may have a circulation pump. 
  2. Install hose bib vacuum breakers. If not already equipped with a built-in vacuum breaker, buy and install an inexpensive hose bib type vacuum breakers on all threaded faucets around your home. This is especially important when using spray attachments for spraying herbicides and pesticides.
  3. Install an approved backflow prevention assembly on all underground lawn irrigation systems. (This is required for the Town of Castle Rock).
  4. Do not connect waste pipes from water softeners or other treatment systems to the sewer, submerged drain pipe, etc.
  5. Do not use a hose to unplug blocked toilets, sewers, etc.
  6. Ensure proper winterization of the sprinkler system to help prevent backflow devices from freezing and breaking.
  7. Install a quick-connect hose adapter / blowout connection after the backflow device on the irrigation system. Having the attachment will prevent using the backflow prevention device port, which, if used, causes undo wear on this device, potentially compromising it. 
  8. Get an annual inspection of backflow prevention devices (especially on irrigation and fire suppression systems). Find certified Cross Connection / Backflow technicians (PDF) registered with the Town.
  9. Learn more about backflow prevention (PDF).
meter stack installation

Cross Connection Backflow Certification

Annual registration is required to be certified as a backflow assembly tester in the Town of Castle Rock. You must complete the registration form and submit a copy of the current tester certification and gauge calibration(s).

Certification / education classes will be held anytime there are updates to the Town’s Municipal Code regarding cross connections / backflow or the Town’s Cross Connection Manual. 

A current list of certified Backflow Prevention Tests (PDF) can be viewed online.

Questions: Email us