Water Department

A cross connection occurs whenever there is an actual or potential physical connection between the public drinking water system and any possible source of contamination. Sources of contamination can include both high hazard materials, which can cause illness or death, and low or non-hazardous materials which are mainly just a nuisance and can cause the water to look, taste or smell unpleasant. Although the high hazards are the primary concern in a cross connection control program, our public water system strives to provide both safe and high quality water to our customers. Whenever there is a loss of pressure in the public water supply, these cross connections can allow unsafe substances to enter the public water supply.

Cross connections can be caused by both permanent and temporary “piping”. An example of a cross connection being permanently piped in is the drain on a water softener. Many times these discharge lines are connected directly to the sewer line without any type of protection. Hot tub, whirlpool and swimming pool fill pipes are other examples of permanently piped cross connections.

1. PRIVATE WELLS AND SECONDARY WATER SOURCES A well or secondary source of water on a property is a potential cross connection. Wells or secondary water sources are prohibited from being connected to the Lincoln Water System. A backflow preventer on the public water supply is always required when secondary sources of water are present on a customer’s property. 2. LAWN IRRIGATION SYSTEMS Underground irrigation systems are a direct cross connection, and the public water supply must be protected with a suitable backflow device. These devices are normally located on the side or back of your home similar to the one pictured. Surface water can be siphoned back into your plumbing system through an automated lawn irrigation system unless a proper backflow device is attached. If the system uses a pump or has fertilizer or chemical injection, additional backflow protection and backflow testing is required. 3. SWIMMING POOLS OR HOT TUBS Pools and hot tubs that are permanently connected to the home plumbing system are direct cross connections and must be protected with a suitable backflow device. An unprotected cross connection could draw pool water and chemicals back into your household plumbing system and public water supply. When filling a pool or hot tub with a hose, never submerge the end as this is another cross connection. Always leave an air gap when filling pools, tubs, sinks or containers. 4. PHOTO, CHEMICAL, BIOLOGICAL, VETERINARIAN OR OTHER LAB FACILITIES Home use of photographic chemicals, process chemicals, biological laboratory supplies, veterinarian supplies or other laboratory chemicals can cause contamination due to an unprotected cross connection. A suitable backflow device is necessary to protect the home plumbing system and public water supply. 5. BOILER SYSTEMS FOR HEATING These systems are not common but do exist in some homes. Normally these systems are in larger homes. Water is used to replenish the boiler which also may have chemicals. This cross connection must be protected with a suitable backflow device to prevent contamination of the home plumbing system and public water supply. 6. HOME MEDICAL, DENTAL OR DIALYSIS EQUIPMENT Similar to equipment found in medical offices, these devices are sometimes used in the home. When connected to the water supply, these cross connections must be protected with a suitable backflow device to prevent contamination of the home plumbing system and public water supply. 7. OTHER POTENTIAL CROSS CONNECTIONS A garden hose submerged in a sink or connected to a container containing chemicals or fertilizer is a serious cross connection. A sudden drop in water pressure from a water main break or from water being used to fight a fire can siphon water back into your home plumbing system or the public water supply. A vacuum breaker is a simple inexpensive device that can be installed on the faucet or hose to prevent contamination. Vacuum breakers are provided on outside faucets on homes built since 1992. Most bathtubs and sinks have an air gap. This space between the highest water level in the fixture and the outlet of the water is the best form of backflow protection. Never leave the end of a hose submerged in a tub, pool or container. Residential fire protection systems, in-home water treatment systems, car washes, solar heating and decorative ponds and soaking tubs are other possible cross connections.