Backflow Prevention Systems help keep our clean drinking water free of contaminated water. Read information below about how it works and why it is important.

What is a Cross-Connection?

A cross connection is a permanent or temporary connection between potable drinking water and anything which can pollute or contaminate the water supply. For example, without backflow protection, attaching a fertilizer sprayer to a garden hose or even placing your hose in a soap bucket for car washing can create a cross connection and possible health hazards.

What is Backflow?

Backflow is the undesirable reversal of flow of non-potable water or other substances through a cross connection and into the piping of a public water system or consumer's potable water system. This reversal of flow or "backflow" can allow contaminated water to flow backward, drawing a contaminant into the water supply. There are two types of backflow - backpressure backflow and back-siphonage backflow.

What Can Cause Backflow?

Backflow can be caused when an unforeseen change in water pressure allowing the water to flow backwards within the water supply piping system from a contaminated source to a drinking water supply. A drop in pressure could be caused by a variety of things, including a water main break or the need to fight a fire.

What does City of Bend Water Utility do to prevent backflow of contaminates?

City of Bend's Cross Connection Control Code requires installation of specific backflow protection assemblies to be installed and tested annually according to currently adopted uniform plumbing code and Oregon Health Division Rules.

Who Can Test Backflow Prevention Devices?

Backflow assemblies must be tested at the time of installation, annually after installation, after repairs and after relocating. Testing in Oregon must be done by Department of Human Services certified backflow testers. Click here for a list of state certified testers. (Search by county)

Who Should I Contact for More Information?

If you have any questions concerning backflow installations, certified testers, or approved backflow prevention device please contact the City of Bend at 541-317-3000, ext. 2.

What is Potable Water?

Water which is safe for human consumption, free from harmful or objectionable materials, as described by the Health Authority.

What is Non-potable Fluid?

Any water, other liquid, gas, or other substance that is not safe for human consumption or is not a part of the public potable water supply as described by the Health Authority.

What is Back-siphonage?

Back-siphonage is caused by negative pressure in the supply piping. Some common causes of back siphonage are:

• High velocities in pipelines.
• Line repair or break that is lower than a service point.
• Lowered main pressure due to high water withdrawal rate, such as firefighting or water main flushing.
• Reduced supply pressure on the suction side of the booster pump.

All potable water systems must be protected against back-siphonage and backflow with approved assemblies. There are numerous types of assemblies available to provide this type of protection. The state law governs the selection and minimum installation standards of assemblies. It is necessary to choose the proper backflow assembly for the use intended.

What is Backpressure Backflow?

Backpressure backflow is the reverse from normal flow direction within a piping system that is the result of the "downstream pressure" being higher than the supply pressure. Therefore, water flows backwards through the pipes and can siphon wastewater or non-potable water into clean drinking water pipes and supply. 

Contact Us

If you have any questions concerning backflow installations, certified testers, or approved backflow prevention assemblies please contact the Safe Drinking Water Program office at (541) 317-3000, etc. 2.