Safe drinking water. It is one of our most precious natural resources. The following information is designed to help us understand what we can do to ensure that the water we use each day is safe. By working together, we can keep our drinking water safe for the good of our families and our community.
Water Safety: Every year across America, hundreds of people are injured or killed because of drinking water system related accidents in their own homes. Examples include drain cleaner being sucked back into the water system and coming out in the shower, and pesticides being sucked back into the garden hose and then being filled into someone’s drinking glass.
While these incidents are not very pleasant to think about, the good news is that we can prevent them.
The key to water system safety is this: whenever safe drinking water leaves the piping, it must do so through a physical air gap or a mechanical backflow preventer, as required by the plumbing code, to keep any contaminated water from entering the safe drinking water.
The water meter is the point where the community water supply enters your system. You must have a water meter and a backflow preventer assembly installed at the water service connection by a licensed plumber in order to be compliant with federal, state and local regulations. You must protect your system from thermal expansion after installing a backflow preventer at the service entrance. Use either an expansion tank or an anti-siphon ball cock assembly with relief feature.
The faucets on your kitchen sink are standard plumbing fixtures. Since they are designed to protect you automatically, you don’t need to do anything to make them safe. The manufacturer does this by providing an air gap between the end of the faucet and the overflow water line of the sink. All you have to do is keep them safe. A typical unsafe condition occurs when a hose on the end of the faucet is submerged into dirty water in the sink. The dirty water can be drawn back into the safe drinking water supply.
When water leaves the drinking water supply system and flows into your toilet tank, the water should be prevented from being drawn back into the water supply. The water in the toilet tank is often treated with cleansing chemicals that are not safe to drink. There is something you can do. Make sure an anti-siphon ballcock assembly is in your toilet tank. This will protect against back-siphonage. The ball cock can also serve as the thermal expansion relief device, if equipped with an auxiliary relief valve. The relief valve should govern the preset pressure to 80 psi or less. You must equip your toilet with the thermal expansion relief device to prevent damage to your plumbing system. A qualified plumber can help you.
The sink and bathtub faucets are generally protected by air gaps. The only thing that can cause a problem is if someone puts a hand-held sprayer on the faucet and it is submerged in bath water. Here you would need a special hose vacuum breaker. There is nothing that needs to be added to increase the safety of your standard bathtub.
Thermal expansion occurs whenever water is heated. The backflow preventer prevents the expanded water produced by a water heater from returning to the community supply. Since water cannot be compressed, the expanded water volume can cause a rapid increase in pressure in the piping. Often the pressure will exceed the setting of the temperature and pressure safely relief valve located on the water heater. This will result in a loss of hot water at the relief valve and, more importantly, it can shorten the life of this very important safety device. CAUTION: Never plug a dripping safely relief valve!! This is important because a water heater can explode if excessive temperature and pressure build up. Water heaters must have a temperature and pressure relief valve. It is your responsibility to check the system every three years to make sure the safety valve is in good working order. The system can be protected by using a potable water expansion tank which absorbs the thermal expansion and maintains a balanced system pressure or by use of an anti-siphon ball cock assembly.
Your washing machine has a built in air gap installed at the factory. You can also install a single lever washing machine shutoff valve that easily shuts off the hot and cold water simultaneously and protects against flooding. There is a possibility that the hose might rupture and flood your basement or laundry room while you are away.
The ordinary garden hose is the most common way to contaminate the water supply. This can happen when one end of a common garden hose is attached to an outdoor faucet (sill cock) and the other end of the hose connects to an aspirator type bottle. Insecticides or other chemicals in the aspirator bottle can be siphoned back into the drinking water supply. You can easily prevent the possibility of this type of contamination by installing a hose bib vacuum breaker. This is a small, inexpensive device that simply attaches to a threaded water faucet.
If you use a hot water system to heat your home you can ensure the protection of the safe drinking water system by making sure a backflow preventer assembly is installed. This will protect you against stagnant or chemically treated water from recirculating back into the water supply. Consult a licensed plumber for more information.
Lawn Irrigation System
If you have a lawn irrigation system you will need a vacuum breaker backflow preventer to protect against lawn and pesticide chemicals from being drawn in from you lawn and back into the water supply. Consult a licensed plumber.
Home Water Conditioning Systems
Water Filtration, softener or treatment: If you have a water treatment or filtration system with a drain hooked up to the sewer, you need an air gap between the drain line and the drain connection.
— Excerpt from Watts ® Regulator public service pamphlet. © Watts Regulator Co., 1998