A cross connection is a connection between a potable drinking water supply and a possible source of contamination or pollution.
Under the provisions of the Safe Drinking Water Act of 1971, the Environmental Protection Agency (EPA) established national standards for safe drinking water. Each state is required to enforce the various regulations of the Safe Drinking Water Act and how it relates to its state laws. To meet these new provisions, the Texas Commission on Environmental Quality (TCEQ) on January 1, 1996, enacted a new state law which requires the public water suppliers to implement and enforce the Cross Connection Control Program requirements located in title 30 Texas Administrative code (TAC) Chapter 290 of the Rules and Regulations for Public Water Suppliers.
In 1999 the City of Garland adopted a new Cross Connection Control and Prevention Ordinance. The Utility conducts periodic water use system inspections as required by this ordinance. These surveys assist in determining if any connections or uses of the potable water supply are inadvertently creating a health hazard to the public.
Backflow is the undesirable reversal of flow in a potable water distribution system.
Water that is always under pressure can only flow in one direction. Then how can water flow in reverse? Water will always flow towards the point of lowest pressure. If a water main were to break or if the fire department opened several fire hydrants to help fight a fire, the pressure in the water main could drop. The demand upstream could cause a reversal in flow.
Cross connections and the possibility of backflow need to be recognized so they do not occur. A garden hose submerged in a hot tub, swimming pool, car radiator, or attached to an insect/fertilizer sprayer could siphon the liquid back into the water main.
Backflow prevention devices are designed to protect the public water system from these types of concerns.