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CREIA Cautions Home Owners about Summer Watering Hazards

July 2003 — The California Real Estate Inspection Association (CREIA) cautions home owners and home buyers about the potential hazard that may occur through the back-flow of water between indoor and outdoor faucets.

The faucets in a home’s kitchen, bathrooms, laundry areas and exterior hose bibbs provide what is know as “potable water”. Potable water is defined as “fit for human consumption.” Non drinking irrigation water is usually termed “non-potable”. Both get their water from the same supply line — that is, the local water company’s water meter located on your lot. This means all water outlets at every location on your property (including both inside and outside) get their water from the same source. This results in a “cross-connection” between your garden hose and your faucets providing drinking water. A cross connection is not a good thing unless there is an anti-siphon or “back-flow” prevention device installed between the potable and irrigation water supply system.

A dangerous cross-connection can occur under the following scenario: Husband is outside fertilizing the lawn with weed-killer fertilizer pellets. Immediately after applying the chemicals he places the hose in a trench or turns on the sprinkler system. While this is occurring Wife is taking a shower and at that moment one of the children is getting a drink of water from the kitchen faucet. The child later becomes sick and a hospital visit reveals weed poison in the child’s blood. This scenario is possible because a change in water pressure can create a siphon effect where the irrigation water containing poisonous chemicals that has leached through the lawn and entered broken or low laying sprinkler heads or coiled hose openings are drawn into the home’s potable water supply.

The California Plumbing Code’s (Chapter 6: Water Supply and Distribution) deals with this hazard by requiring exterior faucets (hose bibbs) and all landscaping water systems to be equipped with properly installed “back-flow” prevention devices. These devices prevent garden water from backing up into your home’s potable water system. However, if your home is an older property, you may not be protected from this potential danger.

A professional inspector can help you determine if your home is protected from cross contamination. All CREIA inspectors are familiar with these devices and they are addressed during their inspections under CREIA’s extensive Standards of Practice.