Is Grand Terrace, CA Tap Water Safe to Drink?
Graded B — but 1,4-Dioxane was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
78.7/100
waterverge.com Grand Terrace, CA — Water Quality Report
Grand Terrace's drinking water received a grade of B (78.7 out of 100), indicating good water quality. The city's 1 water system serves approximately 20,188 residents using groundwater.
Lead levels were measured at 1.5 ppb (90th percentile), well within EPA limits. UCMR 5 testing detected 10 PFAS compounds, with levels exceeding EPA maximum contaminant levels in the water supply.
The system has 3 violations on record, including 1 health-based violation. 2 remain unresolved.
What to know about Grand Terrace's water
Grand Terrace ranks #392 out of 694 cities in California for water quality, placing it below average in the state.
Grand Terrace 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.
Of particular concern: PFAS "forever chemical" levels exceed the 2024 EPA maximum contaminant levels. These synthetic compounds don't break down naturally and require specialized filtration such as reverse osmosis or granular activated carbon.
Hexavalent chromium (chromium-6) was detected at 1.30 µg/L in UCMR 3 testing. While below California's 10 µg/L limit and with no federal MCL set, residents sensitive to this contaminant may consider reverse osmosis filtration.
Water quality score
See methodology →Is Grand Terrace, CA water safe to drink?
Grand Terrace's tap water meets most EPA standards but has areas that warrant attention. With a grade of B (78.7/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 20,188 residents using groundwater (wells).
Recent water quality updates for Grand Terrace
A timeline of significant water quality events, violations, and data updates.
PFAS levels exceed EPA maximum contaminant levels. Reverse osmosis or activated carbon filtration recommended.
Latest EPA compliance and testing data incorporated into Grand Terrace's water quality assessment. Grade: B (78.7/100).
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-3592). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
1 health-based. Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Grand Terrace's water supply.
Well within EPA limits.
PFAS "forever chemicals" exceed EPA maximum contaminant levels. Reverse osmosis or granular activated carbon filtration strongly recommended.
PFAS "forever chemicals" detected
UCMR 5 testing found 10 PFAS compounds in Grand Terrace's water supply. PFAS are synthetic chemicals that persist indefinitely in the environment and the human body.
Violation history
Grand Terrace's water system has 3 total violations on record, including 1 health-based violation. 2 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
San Bernardino 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 City C Nr Highland, San Timoteo C Nr Loma Linda, E Twin C Nr Arrowhead Springs, Santa Ana R A E St Nr San Bernardino, Warm C Nr San Bernardino.
Where does Grand Terrace's water come from?
Grand Terrace's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 20,188 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include City C Nr Highland (river), San Timoteo C Nr Loma Linda (river), E Twin C Nr Arrowhead Springs (river), Santa Ana R A E St Nr San Bernardino (river), Warm C Nr San Bernardino (river).
What Grand Terrace residents can do
Recommended: Reverse osmosis system. This addresses the specific contaminants found in Grand Terrace'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.
Grand Terrace'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 ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Grand Terrace
Industrial polluters nearby
Reported releases to surface water by facilities near Grand Terrace, ranked by pounds discharged annually.
Total reported releases to surface water: 10 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
TELEDYNE BATTERY PRODUCTS REDLANDS, CA92374 | Lead compounds | 4 | 7.3 mi |
FORGED METALS INC FONTANA, CA92337 | Chromium | 4 | 9.3 mi |
OLDCASTLE PRECAST INC FONTANA, CA92337 | Lead compounds | 2 | 9.5 mi |
SIERRA BUILDING PRODUCTS FONTANA, CA92337 | Lead And Lead Compounds | 0 | 8.8 mi |
URETHANE POLYMERS INTERNATIONAL FONTANA, CA92337 | — | — | 8.7 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Grand Terrace
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- ALARK HARD CHROME4.1 mi
- NORTON AIR FORCE BASE LNDFLL 26.3 mi
- STRINGFELLOW8.3 mi
- MARCH AIR FORCE BASE9.2 mi
- NEWMARK GROUND WATER CONTAMINATION9.7 mi
Source: EPA Superfund National Priorities List
Drought conditions
D1 — moderate droughtSan Bernardino 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
San Bernardino 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.
Recommended water filters
Based on contaminants detected in Grand Terrace's water supply, we recommend the following filter types.
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. | 1.5 | 15 | ppb | Inorganic | Safe |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | ND | HI | µg/L | PFAS | Not Detected |
| 8:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | 11.000 | HI | µg/L | PFAS | Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | 0.010 | HI | µg/L | PFAS | Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | 0.013 | HI | µg/L | PFAS | Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | 0.008 | HI | µg/L | PFAS | Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | 0.014 | HI | µg/L | PFAS | Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | 0.014 | HI | µg/L | PFAS | Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | 0.018 | 0.004 | µg/L | PFAS | Over MCL |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | 0.019 | 0.004 | µg/L | PFAS | Over MCL |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | 0.017 | HI | µg/L | PFAS | Detected |
| PFPeS | 0.004 | HI | µg/L | PFAS | Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
See how Grand Terrace compares by contaminant
Explore where Grand Terrace ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Grand Terrace's water comes from
Grand Terrace'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 20,188 people through 1 water system.
Water bodies near Grand Terrace
Grand Terrace is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Grand Terrace
| System Name | PWSID | Population | Source |
|---|---|---|---|
| RIVERSIDE HIGHLAND WATER COMPANY | CA3610057 | 20,188 | GW |
How Grand Terrace compares
Full California rankings →Grand Terrace's score of 78.7/100 is above the average of 57/100 among major California cities. It outscores 8 of 10 nearby cities.
Nearby cities
View California rankings →About Grand Terrace, CA
Wikipedia →Grand Terrace is a city in San Bernardino County, California, United States. The population was 13,150 at the 2020 census, up from 12,040 at the 2010 census. Grand Terrace is located between Highgrove and Colton, along the I-215 and Agua Mansa industrial corridors. The city is located between two mountain ridges: Blue Mountain to the east and the La Loma Hills to the west.
Learn more about your water
Guides and resources related to Grand Terrace's water quality findings.
Explore water quality across San Bernardino
Frequently asked questions
Is Grand Terrace, CA tap water safe to drink?
Grand Terrace's water quality earned a grade of B (78.7/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #392 out of 694 cities tested in California.
What contaminants are in Grand Terrace's water?
Lead was measured at 1.5 ppb (90th percentile). 10 PFAS compounds were detected. 3 violations are on record.
How is Grand Terrace'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 Grand Terrace?
PFAS compounds exceed EPA limits — a reverse osmosis or activated carbon filter is recommended.
Where does Grand Terrace's water come from?
Grand Terrace's water is sourced from Groundwater. The city has 1 water system serving approximately 20,188 residents.
What health violations has Grand Terrace's water system had?
Grand Terrace has 1 health-based violation on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Grand Terrace's groundwater at risk of contamination?
Grand Terrace 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 3 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.
Why does Grand Terrace have so many PFAS compounds in its water?
10 different PFAS "forever chemical" compounds were detected in Grand Terrace's water supply during UCMR 5 testing. PFAS contamination often originates from proximity to military installations (AFFF firefighting foam), airports, industrial manufacturing sites, or wastewater treatment facilities. Some levels exceed the 2024 EPA maximum contaminant levels — a reverse osmosis or NSF-certified activated carbon filter is strongly recommended.
How does Grand Terrace's water compare to other cities?
Grand Terrace ranks #392 out of 694 cities in California (better than 44% of state cities) and #8557 out of 15744 cities nationally (46th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.