Is Thermal, CA Tap Water Safe to Drink?
Graded D, with 171 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
48/100
waterverge.com Thermal, CA — Water Quality Report
Thermal's drinking water received a grade of D (48 out of 100), indicating poor water quality. The city's 17 water systems serve approximately 3,056 residents using groundwater.
Lead levels were measured at 5.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 1172 violations on record, including 127 health-based violations. 171 remain unresolved.
What to know about Thermal's water
Thermal ranks #621 out of 694 cities in California for water quality, placing it among the lowest-rated in the state.
Thermal relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Thermal may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 370 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Thermal, CA water safe to drink?
Thermal's drinking water has significant quality concerns based on EPA testing data. With a grade of D (48/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 17 water systems serve approximately 3,056 residents using groundwater (wells).
Recent water quality updates for Thermal
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Thermal's water quality assessment. Grade: D (48/100).
Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Groundwater Rule, Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule, Lead and Copper Rule, Chlorine.
Federal disaster declaration (FEMA DR-4750). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Thermal's water supply.
Well within EPA limits.
Violation history
Thermal's water system has 1,172 total violations on record, including 127 health-based violations. 171 remain unresolved. 370 violations were issued in the last 5 years.
Flood & environmental risk
Riverside County has experienced 10 federally declared disasters since 1980. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Whitewater R A Indio, Whitewater R Nr Mecca.
Where does Thermal's water come from?
Thermal's drinking water comes from groundwater (wells), supplied by 17 water systems serving approximately 3,056 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Whitewater R A Indio (river), Whitewater R Nr Mecca (river).
What Thermal residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Thermal's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Thermal's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Thermal
Industrial polluters nearby
Reported releases to surface water by facilities near Thermal, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
ARMTEC DEFENSE TECHNOLOGIES COACHELLA, CA92236 | — | — | 4.3 mi |
IMPERIAL WESTERN PRODUCTS INC COACHELLA, CA92236 | — | — | 2.5 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Drought conditions
D1 — moderate droughtRiverside County is currently in D1 (moderate drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Riverside County has experienced 10 federally declared disasters since 1980. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 5.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Thermal compares by contaminant
Explore where Thermal ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Thermal's water comes from
Thermal's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 3,056 people through 17 water systems.
Water bodies near Thermal
Thermal is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Thermal
| System Name | PWSID | Population | Source |
|---|---|---|---|
| Oasis Mobile Home Park | 090605129 | 1,350 | GW |
| Torres-Martinez Clinic | 090605130 | 379 | GWP |
| AMEZCUA - GARCIA WATER | CA3301990 | 316 | GW |
| DD Mobile Home Park | 090605160 | 300 | GW |
| Torres-Martinez Avenue 64 | 090605116 | 180 | GW |
| Montano Ranch | 090600038 | 72 | GW |
| Toledo MHP | 090600021 | 68 | GW |
| Ramon Zaragoza Water | 090600036 | 51 | GW |
| Gamez MHP | 090600029 | 48 | GW |
| El Mesquite MHP | 090600034 | 48 | GW |
| Castro Ranch | 090600027 | 44 | GW |
| Gonzalez MHP | 090600022 | 41 | GW |
| Ranchos Los Ferro MHP | 090600032 | 41 | GW |
| Sandoval MHP | 090600026 | 38 | GW |
| Arellano MHP | 090600023 | 30 | GW |
| Barajas MHP | 090600031 | 25 | GW |
| Garcia MHP | 090600037 | 25 | GWP |
How Thermal compares
Full California rankings →Thermal's score of 48/100 is below the average of 57/100 among major California cities. It outscores 5 of 10 nearby cities.
Nearby cities
View California rankings →ZIP codes served by Thermal
The water systems serving Thermal cover 1 ZIP code. Select any ZIP to see which water systems serve that area.
About Thermal, CA
Wikipedia →Thermal is an unincorporated community within the Coachella Valley in Riverside County, California, United States, located approximately 25 miles (40 km) southeast of Palm Springs and about 9.5 miles (15.3 km) north of the Salton Sea. The community's elevation is 138 feet (42 m) below mean sea level. It is served by area codes 760 and 442 and is in ZIP Code 92274. The population was 2,676 at the 2020 census. For statistical purposes, the United States Census Bureau has defined Thermal a census-designated place (CDP), which does not precisely correspond to the historical community.
Learn more about your water
Guides and resources related to Thermal's water quality findings.
Explore water quality across Riverside
Frequently asked questions
Is Thermal, CA tap water safe to drink?
Thermal's water quality earned a grade of D (48/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #621 out of 694 cities tested in California.
What contaminants are in Thermal's water?
Lead was measured at 5.0 ppb (90th percentile). 1172 violations are on record.
How is Thermal's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Thermal?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Thermal's water come from?
Thermal's water is sourced from Groundwater. The city has 17 water systems serving approximately 3,056 residents.
What health violations has Thermal's water system had?
Thermal has 127 health-based violations on record. The most recent violation was recorded in December 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 171 violations remain unresolved.
Is Thermal's groundwater at risk of contamination?
Thermal uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 1172 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Thermal's water compare to other cities?
Thermal ranks #621 out of 694 cities in California (better than 11% of state cities) and #13526 out of 15744 cities nationally (14th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.