About Drinking Water

Drinking Water In Idaho

Drinking water (also known as potable water) is water that is safe to drink and use in food preparation. In Idaho, groundwater supplies approximately 95% of Idahoans drinking water while surface water supplies the remaining 5%. Safe drinking water is critical to individual and public health, and understanding the quality of your drinking water and what actions to take if it is unsafe are important.

Drinking Water Systems

A drinking water system provides water for human consumption through pipes or other constructed conveyances. A drinking water system is a Public Water System (PWS) if it has at least 15 service connections or regularly serves an average of 25 or more people for at least 60 days per year.

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., cities, towns, apartment complexes, and mobile home parks with their own water supplies).
  • Nontransient Non-community Water System (NTNCWS) – Serves at least 25 of the same people over 6 months per year (e.g., schools, churches, factories, and hospitals that have their own water supplies).
  • Transient Non-community Water System (TNCWS) – Serves an average of at least 25 people, but not necessarily the same people, over 6 months per year (e.g., campgrounds, rest stops, and gas stations that have their own water supplies).

Additionally, a PWS may be a consecutive system if it receives some or all of its finished water from one or more wholesale systems. Delivery from a wholesale system to a consecutive connection may be through direct connection or through the distribution system of one or more consecutive systems.

Drinking Water Protection in Idaho

DEQ’s Drinking Water Bureau protects public health by ensuring drinking water from public water systems is safe and reliable. We work closely with the state’s public drinking water systems to protect drinking water sources, monitor for contaminants, inspect water systems, and review system engineering.

We carry out this work in partnership with Idaho’s seven public health districts. Together, we provide a variety of technical and compliance assistance to public drinking water systems to ensure compliance with state requirements.