Water Utility

Pendleton's Water Supplypendleton water filtration plant

We like to keep you informed about the City’s Water Utility.  There are two sources of drinking water for the City.  The first source consists of 7 deep basalt wells located throughout the city and another deep basalt well located 6 miles east of the city near Mission. The second source is the Umatilla River. 

Water Utility provides for on-going operation, maintenance, and replacement of the water distribution system, customer water meters, well supply, and water filtration plant.  Division provides customer access to safe water for drinking, washing, lawn and garden maintenance, and other commercial and industrial uses.

Water Filtration Plant

Beginning June 13, 2003, the City began withdrawing water from the Umatilla River and filtering it through the new, state-of-the- art membrane filtration Water Filtration Plant (WFP). During the 2008 water year, the WFP provided 88% of the total water used by the City. The remaining 12% came from groundwater wells. Prior to 2003, the City derived 62% of its supply from native groundwater and about 38% from the City’s old “Springs” source. Since the WFP was built, the City has been able to reverse this trend and now relies primarily on surface water, thus reducing declines in the groundwater aquifer.  The WFP utilizes a unique siphon design that adds up to big savings on electric bills. In addition, the roof of the facility is covered with solar panels to generate some of electricity required to operate the plant.

Aquifer Storage and Recovery (ASR)

The City continues to store high-quality drinking water produced in the WFP via its membrane filtration into the basalt aquifer system beneath the City.  That water is stored during the winter months when there is adequate water in the Umatilla River. The stored water is recovered during the summer months when demand is high.  The process is referred to as Aquifer Storage and Recovery (ASR).

The twelve years of the ASR project have demonstrated aquifer recharge, storage and recovery as a viable method for Pendleton to store and recover treated water and assist with reducing native groundwater  declines. During the 2012 water year, the City recharged and stored  approximately 545 million gallons in the underground aquifer.

Distribution System

The water distribution system includes over 108 miles of water lines, many of which are old, cast iron pipe that is 30- to 85-years old and may be brittle and in need of replacement. There are 4,300 isolation valves, many of which also need to be replaced. There are also 9 booster pump stations to move water to higher elevations and 6 reservoirs allowing us to store 6.85 million gallons of water.  This distribution system allows the City to deliver high quality drinking water 365 days a year to over 5700 service connections.

Water system consists of:

  • Ultra-filtration membrane water treatment plant
    • 9.8 million gallons per day: Winter/Spring production
    • 1.6 million gallons per day: Summer/Fall production
    • 15 million gallons per day: future expansion capacity
  • 8 wells
    • 14 million gallons per day: total production capacity
  • 14 booster pump stations
    • 30 total pumps
  • 7 storage tanks
    • 7.2 million gallons total storage
  • 86 miles of water distribution piping
    • 2-inch to 24-inch water lines
    • Ductile Iron, Cast Iron, PVC, Galvanized, Copper, Concrete materials

Water rights:

  • Groundwater permitted
    • 26 million gallons per day
  • Surface Water certificated
    • 13.5 million gallons per day
    • All water of NF Umatilla River

Operating budget for this utility is about $3,300,000 annually, with an average of $800,000 for capital outlay targeted to water system needs.  There are 6 full-time employees and 1 part-time employee equivalent providing these services.

2017 Water Quality Report