We all take the water we drink, bathe in, or prepare food with, for granted. We assume that the water will always be clean and safe to drink. There is, however, a hidden risk that many people don’t give enough attention to – backflow preventers.
Occasionally, situations take place that can impair the quality of drinking water. One common occurrence is the breaking of a private water supply line or a public water main. When something like this happens, water that is polluted or that may contain harmful contaminants can backflow into the potable system, threatening the quality of our drinking water.
Backflow is generally caused by changes in water pressure. For instance, if a water main breaks or a fire hydrant is activated for fire suppression, pressure goes down and this can cause water to flow opposite of the direction it was meant to travel. That means if your irrigation system is connected to your house piping – soil, fecal bacteria and other contaminants that have entered the irrigation heads and piping can “backflow” into your home drinking water, and perhaps into the public water system.
Here’s a true event reported by the Texas Commission on Environmental Quality: While mixing a batch of pesticide, a worker pushed a garden hose into the tank until it touched the bottom. Nearby, city utility workers opened a flush valve, releasing a large flow of water from a water main. Where the worker was mixing the pesticide, the water pressure dropped, and the flow in the hose reversed. Water and pesticides flowed from the pesticide tank back through the hose and into the water lines of the residence.
Fortunately, the worker mixing the pesticide realized the danger and alerted the utility workers, who closed the flush valve before the contamination reached the city’s distribution line. Still, good water and time were wasted.
The solution to this risk is to have a backflow preventer installed. TCEQ requires homeowners with irrigation systems and most commercial buildings to have one. Regular tests and inspections insure that your household plumbing and the public supply is protected.
In addition, residents should install backflow devices on hoses that are used for drip irrigation or hose head sprinklers. The same opposite flow can occur if there is a drop in pressure. These hose backflow preventers are simple, inexpensive devices that provide the same protection.