What is a Cross-Connection?

A cross-connection is a place where dirty water can get into the clean drinking water (“potable” water).?When you turn on your faucet, you expect water to flow out of your faucet.?But under some conditions, dirty water can flow back into the faucet, contaminating the water you drink.?Two situations can cause this: back siphonage and backpressure.

Back siphonage occurs when there is a loss of water pressure in the water supply.?This can happen for a municipal water system during a firefighting emergency or during maintenance.?It can happen on a home well system if there is a loss of power.?During the loss of water pressure, dirty water from a bucket, tub, or sink can be drawn up into the water supply.

Back-siphonage can occur:

·??????If a vegetable sprayer is left in a kitchen sink with dirty water.

·??????If a shower attachment is left in a tub with dirty water.

·??????If a toilet tank fill valve does not meet ASSE #1002, or if the overflow tube is less than an inch below the critical line (CL) marking.

·??????If a garden hose is left in a mud puddle and the hose bib does not have an anti-siphon device.

·??????If a dishwasher does not have an air gap in the drain hose.

·??????If the water softener discharge hose goes directly into the floor drain

Backpressure can occur on boilers if the pressure from the boiler is greater than that of the water supply.?A boiler should have a one-way valve (“backflow preventer”) that prevents this.

When I inspect a home, I look for cross-connections and let the client know how to address them.?Most homes I inspect do have cross-connections.?Cross-connection at the water softener is one of the most common cross-connections I see.?It is also one of the most dangerous since the water softener usually automatically turns on without anyone present, and this can be at a time when there is no water pressure.

See more of my blogs at https://www.easleyservices.com