Plumbing Cross Connection
A home inspector is likely to call out a plumbing cross connection on most home inspections. A plumbing cross-connection is contaminated or non-potable water coming into contact with the home’s potable water supply. Common issues include:
- A dishwasher missing the drain’s high loop
- Hose bibbs missing anti-siphon devices
- Backflow preventer missing on irrigation lines or pool auto fill
- An air gap missing between the faucet and a sink/tub
Why Are These An Issue?
If there is a decrease in the pressure in the supply line going to the house, then this can create back pressure or back siphonage. As a result, non-potable water can be drawn back into the house’s water supply. For example, a break in a public water supply line or perhaps firefighters using a public supply to fight a fire, can cause this back flow. For instance, if the pool doesn’t have an auto-fill backflow preventer and a decrease in pressure occurs, stagnant water from the auto-fill basin could be drawn back into the home’s water pipes. Consequently, this can cause health problems.
With a missing dishwasher high loop, wastewater from the garbage disposal or kitchen sink can make its way back into your dishwasher, thus contaminating your clean dishes. Subsequently, the dishwasher drain line should be secured several inches above the connection to the garbage disposal or waste line with a clamp.
The most common devices use to prevent backflow are an atmospheric vacuum breaker or a double check valve for irrigation and pool auto-fills and an anti-siphon device for a hose bibb. These devices are shown here in order:
How To Fix A Cross Connection?
To fix a cross-connection on a hose bibb, buy a hose bibb anti-siphon device. You can buy these are your local hardware store for less than $10. Screw the device onto the hose bibb and tighten down the locking screw.
For the dishwasher’s high loop, add a clamp to secure the drain hose just under the countertop.
For irrigation and pool auto-fills, contact a licensed plumber to have them install a vacuum breaker.