Idaho water rights

181,734 rights at 271,350 points of diversion in 44 counties · fetched October 8, 2026 from Idaho Department of Water Resources

Open Idaho on the mapHow Idaho water rights work
Groundwater
98,841
Surface water
52,829
Spring
30,064

Idaho at a glance

Doctrine
Prior appropriation (first in time is first in right)
Largest adjudication
Snake River Basin Adjudication, final decree August 25, 2014
Domestic use
Up to 13,000 gallons a day, including up to half an acre of irrigation
Forfeiture
Five continuous years of nonuse
Ownership change
Notify IDWR within 120 days
Right numbers
Basin-sequence-suffix, e.g. 95-1234A

Counties

Counties come from where each right's first point of diversion falls on Census county lines.

Oldest priority dates in Idaho

Seniority is weighed among rights on the same stream system, so this is where the oldest records are rather than a statewide ranking.

Priority date · senior to junior

  • Before 1880
  • 1880–1899
  • 1900–1919
  • 1920–1949
  • 1950–1972
  • 1973–1999
  • 2000 and later
  • No priority date