The City of Lafayette makes every effort to deliver quality drinking water to its customers. From the time we take delivery of the raw water until the treated water reaches your private water system, the water quality is our responsibility.

Many people do not realize that the quality of their drinking water can be compromised at their homes or businesses through seemingly harmless activities.

A sudden drop in pressure in the distribution system can cause water in your private system to flow into the distribution system. This is called backflow. It can happen during a fire event or a water main break or any other circumstance where the pressure in your water system is higher than the pressure in the distribution system.

Contaminants can enter the distribution system when you wash the car, spray pesticides or fertilizers using hose attachments, or fill wading pools. Here’s how it works. If you leave a garden hose in a bucket of soapy water when washing the car, you’ve created a cross connection. If the pressure in the distribution system drops, the soapy water can enter the distribution system through backflow. The same thing can happen if you’ve attached a pesticide or fertilizer sprayer to your hose, if your kitchen hand sprayer is submerged in dish water, or if you have an in-tank toilet bowl cleaner in a mal-functioning toilet. Anything that physically connects a source of contamination to your plumbing system is a cross connection.

Documented backflow incidents include:

• Drinking water contamination by antifreeze
• Human blood in the water system
• Paraquat (herbicide) in the water system
• Propane gas in water mains
• Chlordane and heptachlor (common components of pesticides) in apartment complex water system
• Creosote in water mains

(Source: Colorado Cross-Connection Control Manual – August 2004)

The above incidents were caused by faulty plumbing, human error, and submerged hoses. What they have in common is that they were all made possible because of cross connections on your side and pressure losses in the distribution system. By learning to identify and prevent cross connections, we can all help protect the quality of our drinking water.