Caldwell
Caldwell, ID water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
caldwell city of
groundwater (wells) · local government · PWSID ID3140013
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Caldwell, ID is a small but growing city, with a population near 51,686 and the 6th-largest community in Idaho. Like much of Idaho, Caldwell draws its water primarily from Snake River, Snake River Plain aquifer, and snowpack.
Caldwell's water outlook is shaped most by agricultural demand — the issue that dominates planning across Idaho. Intensive irrigation gives Idaho some of the highest per-capita withdrawals in the nation; aquifer recharge is a growing focus.
Caldwell sits in a state that reuses roughly 9% of treated wastewater (developing programs) and currently experiences exceptional drought.
For the bigger picture, see the Idaho state water profile and the related issues below.
Canyon County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~51,686 (6th-largest in Idaho)
- Primary sources: Snake River, Snake River Plain aquifer, and snowpack
- Drought: exceptional conditions
- State reuse rate: ~9% of wastewater
Statewide drought history
% of Idaho in severe+ drought (Exceptional (D4) now).
Source: U.S. Drought Monitor
Common questions
Is tap water safe in Caldwell?
Caldwell's largest water system, CALDWELL CITY OF, serves about 74,000 people. EPA records show 0 health-based violation(s) since 2016 and a most-recent 90th-percentile lead level of 0 ppb (EPA action level is 15 ppb). Always check your own provider's annual Consumer Confidence Report.
Where does Caldwell get its water?
CALDWELL CITY OF draws primarily from groundwater (wells), part of Idaho's supply from Snake River, Snake River Plain aquifer, snowpack.
Related water issues
Agricultural Demand
Agriculture accounts for the majority of consumptive water use in the West, making farm efficiency and water markets central to any supply solution.
ExploreGroundwater Depletion
Aquifers from the Central Valley to the Ogallala are being pumped faster than they recharge, causing land subsidence and threatening long-term supply.
ExploreDrought
Much of the American West is in a multi-decade dry period that researchers describe as the most severe in over a millennium, reshaping how communities plan for water.
Explore