Customers use water for many different purposes, and the water may come in contact with other substances not fit for consumption. This connection between clean water and other substances is called a “cross-connection.”
A cross-connection is a point in a plumbing system where the potable water supply is connected to a not-potable source. Briefly, a cross-connection exists whenever the drinking water system is or could be connected to any non-potable source (plumbing fixture, equipment used in any plumbing system). Pollutants or contaminants can enter the safe drinking water system through uncontrolled cross-connections when backflow occurs.
It is a logical assumption that because water is always under pressure, it can only flow in one direction. However, can it flow the opposite way from its intended direction? The answer is yes, and when it does it can cause disastrous results. Water will always flow toward the point of lowest pressure.
If a water main in the public water system should break, or if a fire occurred and the fire department opened several hydrants, the pressure in the water mains could drop dramatically, causing a reversal of flow. The potential for this reversal of flow is why Skagit PUD is concerned about the possibility of contaminants or pollutants being siphoned back into the water system.
When the plumbing at a residence is connected to the potable water supply, and it is connected to piping carrying another fluid or gas, such as an air conditioner containing chemicals to kill algae, the contaminant could be drawn back into our water mains. A garden hose submerged into a hot tub or swimming pool, or inserted into your car’s radiator to flush out antifreeze, or attached to a fertilizer sprayer, could siphon these contaminants back into our water mains. Incidents such as these have been documented throughout the country and have happened all too often.
Fortunately, back flow from a cross connection can be prevented. Skagit PUD’s Cross Connections Program protects the water system from contaminants by ensuring that customers have properly installed and maintained back flow prevention devices.
Call Water Quality at (360) 848-2138 for more information.