Town of Tieton Wellhead Protection Plan

The Town of Tieton is located in Yakima County, approximately 10 miles west of the City of Yakima. The Town owns and operates 3 wells:
  • Well Number 1 was drilled in the 1940s and pumps 150 gallons per minute.
  • Well Number 2 was drilled in 1953 and pumps 280 gallons per minute.
  • Well Number 3 was drilled in 1979 and pumps 450 gallons per minute.
  • Well Number 4 was drilled in 2018 and pumps 200 gallons per minute. 
The Town has total certified water rights in the amount of 224 acre-feet. The Town’s sources have historically provided high quality water.

Wellhead Protection Area Delineations

The Town's wellhead protection areas (WHPA) were delineated using an analytical model. The following table summarizes the acreage covered by each WHPA.

Analytical Model Area (Acres)

Source 6-Month 1-Year 5-Year 10-Year
Well Number 1
2.6 5.5 54.9 200.0
Well Number 2
2.1 3.9 19.0 40.3
Well Number 3
2.2 3.7 15.0 30.8
Well Number 4 1.8 3.8 18.8 37.4

Inventory of Potential Contaminant Sources

After delineating the WHPAs associated with the Town’s wells, an inventory of existing and potential sources of groundwater contamination (PDF) was compiled and mapped. The only high risk potential contamination source located near the Town's wells is the presence of agricultural land which may be susceptible to pesticide use.

Contingency Plan

The Town's contingency plan consists of the following components:
  • Susceptibility Assessments: The Washington State Department of Health (DOH) has ranked all of the Town's active wells as having a low susceptibility to contamination.
  • Source Deficiencies: The Town can currently meet the existing and 20-year projected system maximum day demand with all sources in service as required by the DOH. However, if Well Number 3 becomes contaminated, the Town cannot meet its 20-year projected maximum day demand by approximately 240 gallons per minute. The Town plans to consider the benefits of drilling a well in the next 20 years to provide for additional source redundancy and source capacity.
  • Emergency Response: The Town has developed an emergency response plan that includes an emergency call-up list and response procedures for spills, fires, and water supply contamination.
  • Short-Term and Long-Term Water Supplies: Because the distance to the nearest potable water system (City of Yakima) is considerable, bottled water or tanker trucks in conjunction with water conservation/watering restrictions is the most appropriate short-term alternative water supply. New source development and groundwater remediation are the most appropriate long-term alternatives.

Local Management Plan

Local management efforts adopted by the Town include:
  • Posting of street signs at wellhead protection area boundaries
  • An annual school seminar program to promote wellhead protection and water education
  • Distribution of literature
  • Notification of residences and businesses within the Town's wellhead protection areas
View the Regional Management Plan page for more information.