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 Protecting Idahos Water

What is backflow  prevention?

Protection of the public and private water supplies through containment and isolation.

The City of Weiser has a state mandated cross connection control program to protect the public potable water system and requires testing of  backflow prevention assemblies. We also perform surveys to identify possible cross- connections and inspections for proper installation of backflow assemblies.

(Click here for a list of backflow assembly testers)

What do the following piping systems have in common?

  • Portable Pressure Washers
  • Sprayer Hose Attachments
  • Garden Hoses
  • Radiator Flush Kits
  • Fire Sprinklers
  • Cooling & Heating Systems
  • Utility Sinks
  • Swimming Pools
  • Hot Tubs
  • Solar Systems
  • Spas
  • Lawn Irrigation Systems


Each of these water piping systems are cross connections which provide a means for potentially contaminated water and other materials to backflow into the drinking water system.

Backflow occurs whenever water flows in the opposite direction or reverse of the intended direction.


       Suppose that a portable pressure washer is attached to a household faucet. The washer can create a greater pressure than the water main supplying the house. If this scenario occurs, contaminants from the pressure washer, such as solvents, grease, or detergents, could backflow into the drinking water system.Backflow 1

There are other ways that backflow can harm the water supply. For example, pesticides and fertilizers could be back-siphoned from a hose spray attachment if the water pressure in the main water line is reduced due to a main break, scheduled shut-off, during the event of a fire where a fire truck draws a significant amount of water from the system, or a fire hydrant is opened for maintenance.


 If backflow occurs and contaminants enter the water system, people’s health and lives are at risk.


To prevent this potentially hazardous event from occurring, the City of Weiser has enacted a state-mandated cross connection control program. Under this program, backflow prevention assemblies must be installed on all water-using systems and equipment which makes a cross connection between safe drinking water and potential contaminants. Since there are a variety of backflow prevention assemblies on the market, feel free to check with the City’s Water Department staff before selecting and installing such a device.

Annual Testing:

  Each assembly is required to be tested upon installation and then annually. A list of State licensed, City registered testers is available for download in a PDF file on our website.

Click Here For Tester List

BackflowTestLawn irrigation systems 

Why Having a Lawn Sprinkler System Tested is Important 

Backflow events are a major source of waterborne disease. From 1981 to 1998, the Center for Disease Control (CDC) documented 57 waterborne outbreaks related to cross- connections, resulting in 9,734 detected and reported illnesses.

From May 2002 to January 2003, the University of California studied 400 homes. Homes with a cross connection health hazard constituted 95.7% of the homes. 73% of all water uses were through unprotected cross connections.


•  If the due date passes and we have not received a test report, we will make every effort to contact the home or business owner to ensure that they are aware of the situation. If the device is not at that time tested in a timely manner, the customer risks having their water service interrupted until the problem has been taken care of.


  We all need to do our part to protect and preserve our water.

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