What was found in Grand Terrace's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 9648 µg/L 96% of the EPA limit 10000 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Fluoride | 1020 µg/L 26% of the EPA limit 4000 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Barium | 59 µg/L 2.9% of the EPA limit 2000 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Combined Uranium | 18.2972 µg/L 61% of the EPA limit 30 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2018 | 1/1 | SYR4 |
| TTHM | 11.9 µg/L 15% of the EPA limit 80 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Lithium | 11 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Dibromochloromethane | 5.86 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Bromoform | 5.34 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Selenium | 5 µg/L 10% of the EPA limit 50 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Total Haloacetic Acids (HAA5) | 4.405 µg/L 7.3% of the EPA limit 60 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Monochloroacetic Acid | 3.41 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Dibromoacetic Acid | 3.37 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Arsenic | 3.26 µg/L 33% of the EPA limit 10 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Bromodichloromethane | 3 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Chromium | 2.5 µg/L 2.5% of the EPA limit 100 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Monobromoacetic Acid | 1.82 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| Chloroform | 1.8 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2019 | 1/1 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.0471 µg/L 24% of the EPA limit 0.2000 µg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2018 | 1/1 | SYR4 |
| PFOS | 0.0190 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| PFOA | 0.0180 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Pfpea | 0.0170 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Pfhxa | 0.0140 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| PFHXS | 0.0140 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| PFBS | 0.0130 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Pfba | 0.0100 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Pfhpa | 0.0082 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Pfpes | 0.0040 µg/L No EPA limit set Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | UCMR-5 |
| Lead | 0.0015 mg/L 10% of the EPA limit 0.0150 mg/L Main supplier: RIVERSIDE HIGHLAND WATER COMPANY · 20,188 people · 2025 | 1/1 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Grand Terrace
| Supplier | Population served |
|---|---|
| RIVERSIDE HIGHLAND WATER COMPANY | 20,188 |
Frequently asked questions about Grand Terrace tap water
Is Grand Terrace tap water safe to drink?
EPA testing detected 28 contaminants in the water serving Grand Terrace. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Grand Terrace?
1 public water supplier report drinking-water monitoring for Grand Terrace, California to the EPA. Each is listed above with its population served.
What contaminants are in Grand Terrace's water?
The contaminants EPA monitoring detected in Grand Terrace include Nitrate, Fluoride, Barium, Combined Uranium, TTHM. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.