Rancho Cucamonga
Rancho Cucamonga, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
cucamonga valley water district
surface water (rivers/reservoirs) · local government · PWSID CA3610018
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Rancho Cucamonga, CA is a mid-sized city, with a population near 175,236 and the 27th-largest community in California. Like much of California, Rancho Cucamonga draws its water primarily from Sierra snowpack, Colorado River, State Water Project, and groundwater.
Rancho Cucamonga's water outlook is shaped most by drought — the issue that dominates planning across California. Orange County runs the world's largest groundwater replenishment system, and the state adopted direct potable reuse rules in 2023 — but the Central Valley's groundwater overdraft remains severe.
Rancho Cucamonga sits in a state that reuses roughly 23% of treated wastewater (established programs) and currently experiences abnormally dry to moderate drought.
For the bigger picture, see the California state water profile and the related issues below.
San Bernardino County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~175,236 (27th-largest in California)
- Primary sources: Sierra snowpack, Colorado River, State Water Project, and groundwater
- Drought: abnormally dry to moderate conditions
- State reuse rate: ~23% of wastewater
Statewide drought history
% of California in severe+ drought (Moderate (D1) now).
Source: U.S. Drought Monitor
Common questions
Is tap water safe in Rancho Cucamonga?
Rancho Cucamonga's largest water system, CUCAMONGA VALLEY WATER DISTRICT, serves about 211,069 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 Rancho Cucamonga get its water?
CUCAMONGA VALLEY WATER DISTRICT draws primarily from surface water (rivers/reservoirs), part of California's supply from Sierra snowpack, Colorado River, State Water Project.
Related water issues
Drought
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.
ExploreColorado River
The river that supplies 40 million people has lost roughly a fifth of its flow since 2000, forcing a renegotiation of how seven states share the water.
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.
ExplorePotable Reuse
Advanced purification turns treated wastewater into water that meets or exceeds drinking-water standards — increasingly essential in water-stressed regions.
Explore