Department of
Environmental Quality

Idaho's rules for public drinking water systems require that all community and nontransient noncommunity public drinking water systems and distribution facilities be classified based on indicators of potential health risk. Criteria used to determine the potential health risks include the system's complexity, size, and source water for treatment facilities; complexity and size of distribution systems; and other criteria deemed appropriate. Systems are classified by type (treatment or distribution) and class. Classifications range from "Very Small" to "Class I, II, III, or IV." The rules also require that public drinking water systems be staffed by licensed operators based on the system classification.

Determining a System's Classification

The owner of each public water system must calculate its classification to ensure its operators, and in particular, the responsible and substitute responsible charge operators, are properly licensed. A worksheet has been developed for both treatment and distribution systems to assist in determining system classification. The worksheet must be filled out and submitted to DEQ every five years or any time a substantive change or upgrade is made to the treatment or distribution system. Based on the information provided in the worksheet, DEQ determines the system's classification.

• Drinking Water Treatment System Classification Worksheet   |  
  Word Format
• Drinking Water Distribution System Classification Worksheet  |  
  Word Format

Current Public Drinking Water System Classification Ratings

DEQ maintains and periodically updates a list of drinking water treatment and distribution systems that have submitted classification worksheets and received verification of the official system classification.

• Public Water Systems Classification List

Note: This list is a snapshot in time according to the date shown on the list.

Drinking Water System Name/Address Changes

The drinking water system owner or the owner's designee should contact the local DEQ Regional Office or Idaho Public Health District to report any changes in the name of the system, the name of the legal owner of the system, the owner's contact information, or the system's mailing or physical address.