According to the Colorado Primary Drinking Water Regulation, “A public water system or consecutive water distribution system of a public water system will have no uncontrolled cross-connections to a pipe, fixture, or supply, any of which contain water not meeting provisions of the drinking water regulations.”
A cross-connection is any point in a water distribution system where chemical, biological, or radiological contaminants may come into contact with potable water.
During a backflow event, these pollutants/contaminants could be drawn or pushed back into the potable water system. A backflow prevention assembly installed at every point of cross connection prevents polluted/contaminated water from entering the potable water distribution system.
Pollutants from a cross-connection can be non-hazardous to human health, causing aesthetic problems such as taste, odor, and color problems.
Contaminants from a cross-connection can be toxic, causing illness or death to those who unsuspectingly consume the contaminated water.
Common cross-connections requiring backflow assemblies are lawn sprinkler systems, commercial boiler systems, residential boiler systems with anti-freeze, and fire suppression systems.
1. Lawn sprinkler systems are exposed to chemicals such as fertilizers, insecticides, and herbicides.
2. Commercial boiler systems contain large amounts of non-potable water because the water is constantly reused, which causes the disinfectant properties to disintegrate.
3. Residential boiler systems with anti-freeze, or anti-freeze connections, can be contaminated with automotive anti-freeze, which is very toxic and a health hazard if consumed.
4. Fire suppression systems have stagnant water that presents a pollution problem, causing taste, odor, and color problems, unless anti-freeze is introduced, which then causes a health hazard.