FAQs

Cross Connection Control Program

• 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.

• What can cause backflow?

  Backflow can be caused when an unforeseen change in water pressure allows 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 Pendleton do to Prevent backflow of contaminates?

  City of Pendleton requires installation of specific backflow prevention assemblies to be installed and tested annually according to currently adopted uniform plumbing code and Oregon Health Authority 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 Oregon Health Authority-certified backflow testers.

• What is potable water?

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

• What is backsiphonage?

  Backsiphonage is a type of backflow caused by negative pressure in the supply piping.  Some common causes of backsiphonage are:

  • High velocities in pipe lines.
  • Line repair or break that is lower than a service point.
  • Lowered main pressure due to high water withdrawal rate, such as fire\fighting or water main flushing.
  • Reduced supply pressure on the suction side of the booster pump.
• What is backpressure?

  Backpressure is a backflow that 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.