Potential Contamination

In order to facilitate the update of this plan according to the biennial schedule outlined in WAC 246-290-135, existing, easily-accessible databases of potential contamination sources were explored.

These sources form the foundation of the inventory database for each community's wellhead protection plan.


The following databases are available from the Washington State Department of Ecology:
  • Businesses that own and operate underground storage tanks (USTs)
  • Businesses that treat, transport, store, or dispose of hazardous wastes
  • Businesses which handle substances that require a material safety data sheet (MSDS)
  • Confirmed or suspected sites of contamination
  • Sites occupied by leaking underground storage tanks (LUSTs)
  • Solid waste facilities or landfills
The inventory database was augmented with a telephone book search of high risk businesses and a windshield survey of the WHPAs. The following potential contamination sources were identified in the windshield survey:
  • Airports
  • Cemeteries and graveyards
  • Chemical storage areas
  • Country clubs and golf courses
  • Dry cleaners
  • Electronic equipment manufacturers and storage
  • Jewelry and metal plating shops
  • Logging and lumber facilities
  • Pesticide application areas
  • Population centers (greater than one house per acre)
  • Private wells
  • Railroad corridors
  • Railroad tracks and yards
  • Recycling and reduction facilities
  • Septic tanks
  • Stormwater injection wells and catch basins


As part of the regional wellhead protection management plan, Yakima County stores and maintains the regional contaminant source inventory (PDF) on its Geographic Information System (GIS). The GIS links contaminant inventory and water quality database information to regional mapping for easy storage, retrieval, and analysis of the data. Correlation of these inventory sources with the water quality database is used to identify trends that can be targeted in management efforts. The following water quality parameters are available from the Washington State Department of Health:
  • Inorganic Chemical and Physical Constituents (LOCs)
  • Nitrates
  • Radon
  • Synthetic Organic Compounds (SOCs)
  • Trihalomethanes
  • Volatile Organic Compounds (VOCs)