California
California sits in the Pacific and draws its water primarily from Sierra snowpack, Colorado River, State Water Project, and groundwater. With roughly 39 million residents, the state has an established water reuse program, reusing an estimated 23% of its treated wastewater.
Californiawater quality & safety
Top violation drivers in California
| Contaminant / rule | Systems |
|---|---|
| LEAD AND COPPER RULE REVISIONS | 507 |
| Arsenic | 133 |
| Nitrate | 122 |
| Revised Total Coliform Rule | 118 |
| TTHM | 88 |
| Total Haloacetic Acids (HAA5) | 70 |
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1 · health-based violations since 2016
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.
On the U.S. Drought Monitor scale, California currently tracks around abnormally dry to moderate conditions. California has 3,071 community water systems serving about 44 million people; EPA records show 1,014 of them (33%) with a health-based Safe Drinking Water Act violation since 2016. The pages below break down the water issues that matter most here and the communities working on solutions.
Drought history — severe+ extent
% of California in severe drought or worse (D2+) each late summer.
Source: U.S. Drought Monitor (NDMC/UNL, USDA, NOAA) · latest 2026-06-09
Water use (USGS 2015)
- Per-capita (public supply)
- 137 gpcd
- Total withdrawals
- 28.8 Bgal/d
- From groundwater
- 66.6%
- Irrigation share
- 66%
- Wastewater reused (est.)
- ~23%
Primary water sources
- ≈ Sierra snowpack
- ≈ Colorado River
- ≈ State Water Project
- ≈ groundwater
Common questions
Is tap water safe in California?
California has 3,071 community water systems serving about 44 million people. EPA records show 1,014 of them (33%) with at least one health-based Safe Drinking Water Act violation since 2016, and 37 system(s) over the federal lead action level. Most large systems meet standards; check your specific city and your utility's annual report.
What contaminants are most common in California's water?
The most frequent health-based violations involve LEAD AND COPPER RULE REVISIONS, Arsenic, Nitrate.
How much water does California use per person?
Public water systems in California withdraw about 137 gallons per person per day (USGS 2015), drawing 66.6% of fresh water from groundwater.
How bad is the drought in California?
As of 2026-06-09, 7.4% of California is in drought (D1+) and 0% is in severe drought or worse, per the U.S. Drought Monitor.
Cities in California
30 trackedLos Angeles
L.A. imports much of its water from hundreds of miles away and is racing to localize supply through recycling and stormwater capture, with a goal to recycle all its wastewater.
San Diego
San Diego is building Pure Water, a multibillion-dollar program set to supply nearly half the city's water through purification, alongside the largest desalination plant in the country.
San Jose
San Jose, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
San Francisco
San Francisco, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Fresno
Fresno, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Sacramento
Sacramento, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Long Beach
Long Beach, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Oakland
Oakland, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Bakersfield
Bakersfield, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Anaheim
Anaheim, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Santa Ana
Santa Ana, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Riverside
Riverside, CA water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Key issues in California
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.
ExploreStormwater Capture
Cities are reengineering streets and parks to capture rain that once ran to the sea, recharging aquifers and reducing flooding at the same time.
ExploreSaltwater Intrusion
As coastal aquifers are over-pumped and seas rise, saltwater pushes inland and contaminates freshwater supplies for cities from Florida to California.
ExploreSnowpack Decline
Mountain snow is the West's largest reservoir. As warming shifts snow to rain and melts it earlier, the timing and reliability of water supply are unraveling.
ExploreFlood Management
Climate change is intensifying both droughts and floods. The frontier is managing them together — capturing floodwater to recharge depleted aquifers.
ExploreMicroplastics
Tiny plastic particles are turning up in tap and bottled water worldwide. Science on health effects is young, but regulators are starting to act.
ExploreWater Rights
In the West, water is governed by 'first in time, first in right' — a century-old legal system now colliding with scarcity, cities, and the environment.
ExploreAnalysis featuring California
Mapping America's Worst Drinking-Water Violations
Oklahoma's water systems break the rules at the highest rate in the country, while Texas racks up the most violations by sheer volume. The gap between those two numbers is the whole story.
Read analysisInside the World's Largest Water Recycling System
Orange County's Groundwater Replenishment System turns sewage into drinking water for a million people — and quietly became the proof point for reuse nationwide.
Read analysisWhat Is Potable Reuse? A Plain-English Guide to Drinking Recycled Water
Direct vs. indirect, the treatment train, and the 'yuck factor' — everything you need to understand the technology reshaping American water.
Read analysisThe 2026 Colorado River Reckoning, Explained
Seven states must agree on how to share a shrinking river after 2026. Here's what's at stake for 40 million people.
Read analysisCalifornia's Biggest Reservoir Is Melting Earlier Every Year
The Sierra snowpack stores a third of the state's water. As it melts sooner, the entire system built around its timing is straining.
Read analysisLos Angeles Is Learning to Drink the Rain
A city built to flush stormwater to the sea is now racing to capture it — recharging aquifers and cutting reliance on imported water.
Read analysisCash for Grass: How Turf Rebates Conquered the West
The Las Vegas model — paying residents to tear out lawns — has become the most replicated water-conservation program in the arid United States.
Read analysis