Skagit Public Utility District
Home MenuPrevent Cross-Connection Control Issues
Customers use water for many purposes that can potentially subject it to other substances, making it unfit for consumption. This connection between clean water and other substances is called a “cross-connection.”
Keeping Contaminants Out of Your Water
It is a logical assumption that water can only flow in one direction because it is constantly under pressure. However, can it flow the opposite way from its intended direction? The answer is yes; 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 water mains' pressure could drop dramatically, causing a flow reversal. The potential for this flow reversal 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 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, 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, backflow from a cross-connection can be prevented. Skagit PUD’s Cross-Connection Program protects the water system from contaminants by ensuring that customers have properly installed and maintained backflow prevention devices.
Call Cross-Connection Control at (360) 848-2138 for more information.
Frequently Asked Questions
Cross-Connection Standard Details
Skagit PUD has adopted standard specifications for the installation of backflow prevention assemblies.
See these standard drawings for more information:
- Standard Installation of 2" and Smaller Reduced Pressure Backflow Assembly (RPBA-1)
- Standard Installation of 2-1/2" and Larger Reduced Pressure Backflow Assembly (RBA-2)
- Standard Installation of Double-Check Detector Assembly (WDCDA-1)
- Double-Check Valve Assembly (DCVA-1)
Backflow Prevention
Under current state regulations, the water purveyor protects the public water system from contamination via cross-connections. The water purveyor’s responsibility for cross-connection control begins at the water supply and ends at the point of delivery to the consumer’s water system, the water meter. The “Authority Having Jurisdiction” (e.g., City or County) is responsible for cross-connection protection within the consumer’s water system and property lines.
Skagit PUD may require premise isolation of a facility to protect the public water supply. Appropriate planning should address the possible requirement of a Reduced Pressure Backflow Assembly (RPBA) or Double Check Valve Assembly (DCVA) to be installed immediately after any metered water service or fire service connection, now or in the future. DCVAs can be installed below ground with brass plugs in the test cocks. RPBAs are installed above ground with a minimum of 12-inches clearance below the assembly to finish grade and protected from freezing and abuse. If the RPBA is installed in an above-ground enclosure, the enclosure must have a drain opening adequately sized to handle the relief valve's maximum flow.
Under WAC 246-290, backflow prevention assemblies that appear on the USC-Approved Assemblies List are acceptable for protection of the public water system. Skagit PUD requires copies of the initial test(s) of the requisite backflow prevention assemblies. The owner is responsible for subsequent annual testing and providing the test results to Skagit PUD.