Backflow prevention protects your home’s drinking water from contamination. Understanding how backflow happens, where the risks are and when a device needs attention helps you keep your family’s water safe.
What is backflow?
Backflow happens when water flows the wrong way: out of your plumbing, or out of something connected to it such as an irrigation system, and back toward the clean water supply. That reverse flow can carry contaminants with it. It usually has one of two causes:
- Back-siphonage: a sudden drop in supply pressure, for example from a water main break or heavy firefighting demand nearby, can pull water backward out of your pipes.
- Backpressure: the pressure on your side of the system rises above the supply pressure, for example because of a pump, a boiler or an elevated tank, and pushes water back toward the supply.
What backflow prevention means
Backflow prevention means stopping that reverse flow wherever your plumbing connects to something that could contaminate it. This kind of connection is called a cross-connection. Protection can be as simple as an air gap at a fixture, or it can be a mechanical backflow prevention assembly with check valves that only let water move in one direction. Common assemblies include reduced pressure (RP) assemblies, double check (DC) assemblies and pressure vacuum breakers (PVB). Which one is needed depends on the hazard and on what your water provider requires.
Common backflow risks around a home or business
- Lawn irrigation systems, where water can pick up fertilizer, pesticides and soil.
- Garden hoses left in buckets, pools, ponds or spray tanks.
- Pools, spas and fountains with their own pumps and chemical treatment.
- Fire sprinkler systems, which hold standing water for long periods.
- Boilers and other equipment that can create backpressure or contain treatment chemicals.
- Commercial equipment connected to the water supply, such as in kitchens, car washes and dental or medical offices.
Why backflow prevention is essential
- Protects Drinking Water Preventing backflow ensures that your drinking water remains clean and free from harmful contaminants.
- Complies with Regulations Many local regulations require backflow prevention devices to protect public water supplies. Compliance avoids fines and ensures safety.
- Prevents Health Hazards Contaminated water can cause serious health issues. Backflow prevention protects your family from these risks.
- Avoids Plumbing Damage Backflow can cause damage to your plumbing system. Prevention helps maintain the integrity and longevity of your pipes and fixtures.
Why proper inspection and testing matter
A backflow assembly is a mechanical device. Springs weaken, rubber parts wear and debris can stop a check valve from sealing, so a device can fail without any sign you would notice at the tap. That is why water providers require testable assemblies to be checked regularly. In the City of San Diego, for example, backflow assemblies must be tested at least once a year by a tester who holds a current backflow tester certificate and is on the City’s approved tester list. Requirements differ between water providers, so follow the notice you receive from yours. Our guide to backflow testing in San Diego explains what happens during a test.
Inspection matters at installation too. An assembly has to be the right type for the hazard, installed in an approved location and orientation, and accessible for testing. A device that is the wrong type or is installed incorrectly may not protect your water, even if it looks fine.
When to contact a qualified plumbing professional
- You have received a testing or compliance notice from your water provider.
- A backflow assembly fails its test, leaks, or discharges water from its relief valve.
- You are adding irrigation, a pool, a fire sprinkler system, a boiler or commercial equipment.
- Your water looks cloudy or discolored, or tastes or smells unusual. In that case, also contact your water provider.
- You are not sure whether your property needs a backflow device at all.
Related plumbing services
Backflow protection is closely linked to water pressure. Pressure that is too high or that swings sharply puts extra strain on pipes, fixtures and backflow devices, so it is worth having your water pressure regulator checked at the same time.
Fraser Plumbing’s backflow prevention services
Fraser Plumbing provides installation, inspection, and maintenance of backflow prevention devices. Our experienced technicians ensure your system meets all safety standards.
Conclusion
Backflow prevention is a vital aspect of home plumbing maintenance. Contact Fraser Plumbing to install or service your backflow prevention device and keep your water supply safe.
