Protecting Public Health and the Environment.

Public Water Systems in Idaho

What is a Public Water System?

A public water system (PWS) provides water to the public for human consumption through pipes or other constructed conveyances, if such system has at least 15 service connections or regularly serves an average of at least 25 individuals at least 60 days out of the year. Idaho currently has ±1,960 PWSs.

A PWS can be one of three types:

Community Water System

Serves at least 15 service connections or 25 people year-round in their primary residences (e.g., most cities and towns, apartments, and mobile home parks with their own water supplies). About 38% of Idaho's PWSs are classified as community water systems.

Nontransient Noncommunity Water System (NTNCWS)

Serves at least 25 of the same persons over 6 months per year (e.g., schools, churches, nursing homes, and factories, and hospitals that have their own water source). Almost 12% of Idaho's PWSs fit into this category.

Transient Noncommunity Water Systems (TNCWS)

Serves an average of at least 25 persons (but not the same 25) less than 6 months per year (e.g., campgrounds or highway rest stops that have their own water source). About half of Idaho's PWSs meet these criteria.


Staff Contacts

Drinking Water Bureau Chief
Tyler Fortunati
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0140
Tyler.Fortunati@deq.idaho.gov