Compliance record
Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.
4
health-based violations
6
violations on file
0
still open
| Violation | Type | Status | Period |
|---|---|---|---|
| MCL | Health-based | Resolved | 1993-08-01 → 1993-08-31 |
| MCL | Health-based | Resolved | 1993-08-01 → 1993-08-31 |
| MCL | Health-based | Resolved | 1993-07-01 → 1993-07-31 |
| MCL | Health-based | Resolved | 1993-07-01 → 1993-07-31 |
| MR | Monitoring | Resolved | 2013-01-01 → 2013-12-31 |
| MR | Monitoring | Resolved | 2013-01-01 → 2013-12-31 |
PFAS detected
PFAS are industrial “forever chemicals”. These are the EPA's latest
nationwide test results (2023–2025).
Other contaminants detected
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 this
system's samples — over 100% is worth reading, but is not by itself a
violation. Where a single sample came in higher than that percentile, it
is noted under the bar. Formal violations are listed separately.
| Contaminant | Level vs EPA limit | Detection rate | Source | Period |
|---|---|---|---|---|
| Nitrate | 5118.9 µg/L 51% of the EPA limit 10000 µg/L
worst single sample: 9944 µg/L | 2228/2238 | SYR4 | 2012–2019 |
| Trichloroethylene | 6.9 µg/L 138% of the EPA limit, at the 95th percentile of samples — 5 µg/L
worst single sample: 10 µg/L | 453/873 | SYR4 | 2012–2019 |
| 1,2-Dichloropropane | 0.9410 µg/L 19% of the EPA limit 5 µg/L
worst single sample: 1.2 µg/L | 219/843 | SYR4 | 2012–2019 |
| Tetrachloroethylene | 0.9800 µg/L 20% of the EPA limit 5 µg/L
worst single sample: 1.5 µg/L | 171/843 | SYR4 | 2012–2019 |
| Fluoride | 400 µg/L 10% of the EPA limit 4000 µg/L | 80/80 | SYR4 | 2012–2019 |
| TTHM | 22.35 µg/L 28% of the EPA limit 80 µg/L
worst single sample: 35 µg/L | 74/509 | SYR4 | 2012–2019 |
| Chloroform | 4.96 µg/L No EPA limit set
worst single sample: 7.7 µg/L | 68/509 | SYR4 | 2012–2019 |
| Dibromochloromethane | 8.1 µg/L No EPA limit set
worst single sample: 12 µg/L | 67/509 | SYR4 | 2012–2019 |
| Bromodichloromethane | 7.51 µg/L No EPA limit set
worst single sample: 10 µg/L | 59/509 | SYR4 | 2012–2019 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L | 28/28 | LCR | 2024 |
| Total Haloacetic Acids (HAA5) | 14.2 µg/L 24% of the EPA limit 60 µg/L
worst single sample: 16 µg/L | 25/92 | SYR4 | 2012–2019 |
| Bromoform | 3.5 µg/L No EPA limit set
worst single sample: 4.4 µg/L | 24/509 | SYR4 | 2012–2019 |
| Arsenic | 7.88 µg/L 79% of the EPA limit 10 µg/L
worst single sample: 17 µg/L | 17/55 | SYR4 | 2012–2019 |
| Monochloroacetic Acid | 13.2 µg/L No EPA limit set
worst single sample: 14 µg/L | 17/92 | SYR4 | 2012–2019 |
| Combined Uranium | 4.93935 µg/L 16% of the EPA limit 30 µg/L
worst single sample: 6.7944 µg/L | 16/16 | SYR4 | 2014–2019 |
| Dichloroacetic Acid | 3.41 µg/L No EPA limit set
worst single sample: 3.8 µg/L | 14/92 | SYR4 | 2012–2019 |
| Chromium | 3.16 µg/L 3.2% of the EPA limit 100 µg/L
worst single sample: 3.4 µg/L | 9/25 | SYR4 | 2012–2019 |
| Gross Beta Particle Activity | 1.728 pCi/L No EPA limit set
worst single sample: 1.82 pCi/L | 9/12 | SYR4 | 2013–2016 |
| Barium | 46.3 µg/L 2.3% of the EPA limit 2000 µg/L
worst single sample: 55 µg/L | 7/25 | SYR4 | 2012–2019 |
| Dibromoacetic Acid | 2.48 µg/L No EPA limit set
worst single sample: 2.6 µg/L | 7/92 | SYR4 | 2012–2019 |
| 1,1-Dichloroethylene | 0.5750 µg/L 8.2% of the EPA limit 7 µg/L
worst single sample: 0.6400 µg/L | 6/843 | SYR4 | 2012–2019 |
| Toluene | 49.6 µg/L 5% of the EPA limit 1000 µg/L
worst single sample: 57 µg/L | 5/842 | SYR4 | 2012–2019 |
| Trichloroacetic Acid | 2.08 µg/L No EPA limit set
worst single sample: 2.2 µg/L | 5/92 | SYR4 | 2012–2019 |
| Styrene | 3.31 µg/L 3.3% of the EPA limit 100 µg/L
worst single sample: 3.7 µg/L | 4/843 | SYR4 | 2012–2019 |
| 1,1,2-Trichloroethane | 0.5600 µg/L 11% of the EPA limit 5 µg/L
worst single sample: 0.5800 µg/L | 3/843 | SYR4 | 2012–2019 |
| Ethylbenzene | 1.233 µg/L 0.2% of the EPA limit 700 µg/L
worst single sample: 1.3 µg/L | 3/842 | SYR4 | 2012–2019 |
| Monobromoacetic Acid | 1.69 µg/L No EPA limit set
worst single sample: 1.7 µg/L | 3/92 | SYR4 | 2012–2019 |
| 1,2,4-Trichlorobenzene | 0.5600 µg/L 0.8% of the EPA limit 70 µg/L | 2/843 | SYR4 | 2012–2019 |
| 1,2-Dichloroethane | 0.8000 µg/L 16% of the EPA limit 5 µg/L | 2/843 | SYR4 | 2012–2019 |
| Dichloromethane | 3.075 µg/L 62% of the EPA limit 5 µg/L
worst single sample: 3.1 µg/L | 2/840 | SYR4 | 2012–2019 |
| Nitrate-Nitrite | 3295 µg/L 33% of the EPA limit 10000 µg/L
worst single sample: 3300 µg/L | 2/2 | SYR4 | 2016–2019 |
| Xylenes, Total | 1.995 µg/L 0% of the EPA limit 10000 µg/L
worst single sample: 2 µg/L | 2/840 | SYR4 | 2012–2019 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.0220 µg/L 11% of the EPA limit 0.2000 µg/L | 1/23 | SYR4 | 2013–2019 |
| Copper | 140 µg/L 11% of the EPA limit 1300 µg/L | 1/72 | SYR4 | 2012–2019 |
| Di(2-ethylhexyl) Phthalate | 11 µg/L 183% of the EPA limit, at the 95th percentile of samples — 6 µg/L | 1/14 | SYR4 | 2014–2019 |
70 contaminants tested, none detected
1,1,1-Trichloroethane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDalaponDi(2-ethylhexyl) AdipateDinosebDiquatEthylene DibromideEndothallEndrinGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorNetfosaaNfdhaNmefosaaNitriteOxamylPfdaPfdoaPfeesaPfhpsPfmbaPfmpaPFNAPFOSPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineThallium, TotalTotal Polychlorinated Biphenyls (PCB)ToxapheneVinyl Chloridecis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene
Utility contact
Frequently asked questions about Rialto, City of
Is Rialto, City of tap water safe to drink?
EPA monitoring detected 42 contaminants in Rialto, City of's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.
What contaminants were detected in Rialto, City of's water?
EPA monitoring detected Nitrate, Trichloroethylene, 1,2-Dichloropropane, Tetrachloroethylene, Fluoride, and others. The full list with the level and data source for each is above.
How many people does Rialto, City of serve?
Rialto, City of reports serving 54,453 people in California, per its EPA record.
Has Rialto, City of had any water quality violations?
The EPA has 6 violations on file for Rialto, City of, of which 4 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.
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.