November and December are good times to plant trees and shrubs. Residents tend to water a new planting with a garden hose placed at its base. Often the hose is left to trickle water to keep the root ball damp. However, this is a dangerous situation which can result in backflow, i.e., water in a puddle can serve as a reservoir to allow flow back through the hose into the MUD water lines. The contamination can range from soil and silt, to pesticides, herbicides and fertilizers.
You may ask, "How can this happen?" If a Hays Utility work crew opens a water main to make repairs or when water is drawn from a fire hydrant to fight a fire, a situation occurs that creates a partial vacuum in parts of the MUD's water lines, which in turn can cause water to flow in reverse and draw in contaminated water.
As unlikely as this sounds, documented cases of backflow have been observed across Texas, and the situations described above are only two of the many that are possible. Yet the problem is easily prevented by installing a vacuum breaker on the end of your house's exterior faucet. A vacuum breaker permits normal water flow, but backflow causes its diaphragm to close and its vent holes to open. Water flow is blocked by the closed diaphragm and the vent holes let in air to break the vacuum. This way, contaminated water cannot enter the MUD water lines - it is stopped at the vacuum breakers.
The picture below shows a Watts NF8C. Its sliding sleeve opens to permit the outside faucet to be drained during a winter freeze. To install this device, you tighten it on the end of the exterior faucet, then turn its setscrew until it snaps off. The setscrew prevents the device from being removed easily. It costs about $20.
