Drinking water quality · 2023
· Verified
What's in Ontario Municipal Utilities Company, CA tap water
121 contaminants were measured in the Ontario Municipal Utilities Company, CA water system's 2023 annual report. Each is shown below against its federal limit — 2 sit at or above that limit.
- Reporting year
- 2023
- Contaminants measured
- 121
- Over federal limit
- 2
- Approaching the limit
- 0
- Worst contaminant
- PFOA
- Service area
- CA
7.5× the limit
state-level CCR
PFAS — EPA UCMR5 (2023–2025)
2 PFAS compounds above EPA limits in Ontario Municipal Utilities Company, CA
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFOA (Perfluorooctanoic acid)
● Over EPA limit (7.5×)Measured 30 ng/LEPA limit 4 ng/LSample year 2023Samples 1 detect / 35
2.2× the national p90 (13.649999999999999 ng/L across detecting U.S. systems)
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (1.3×)Measured 5.2 ng/LEPA limit 4 ng/LSample year 2023Samples 1 detect / 35
below national p90 (19.900000000000006 ng/L across detecting U.S. systems)
PFHxS (Perfluorohexane sulfonic acid)
● Below limitMeasured 4.2 ng/LEPA limit 10 ng/LSample year 2023Samples 1 detect / 35
below national p90 (12.049999999999997 ng/L across detecting U.S. systems)
PFPeA
● Detected (no federal limit)Measured 6.7 ng/LSample year 2023Samples 2 detect / 35
below national p90 (15.95999999999999 ng/L across detecting U.S. systems)
PFHxA
● Detected (no federal limit)Measured 7.1 ng/LSample year 2023Samples 1 detect / 35
near national p90 (12.190000000000003 ng/L across detecting U.S. systems)
PFBA
● Detected (no federal limit)Measured 6.4 ng/LSample year 2023Samples 2 detect / 35
below national p90 (18 ng/L across detecting U.S. systems)
PWSID CA3610034 · Source: EPA UCMR5. Limits per EPA's April 2024 PFAS National Primary Drinking Water Regulation. PFAS values reported in nanograms per liter (ng/L) — note that 1 ng/L = 1 part per trillion.
Where your water comes from · EPA SDWIS
Ontario Municipal Utilities Company, CA's drinking water comes from ground water, drawn from 18 sources.
Source
18ground water
- WELL · 14
- WELL NO. · 3
- WELL 41 - RAW
Treatment
18treatment plants
- WELL 43 - TREATED (CL2)
- WELL 37 AND 39 IX FINISHED BLEND EFF
- WELLS 37 AND 39 IX COMBINED VESSEL EFF
- + 15 more
Distribution
0storage units
Also buys water from CHINO BASIN DESALTER AUTH. - DESALTER 2, JURUPA COMMUNITY SD, and 3 more.
Source: EPA SDWIS facilities inventory. Methodology.
Historical readings · EPA Six-Year Review (2012–2019)
3 contaminants historically over EPA limits in Ontario Municipal Utilities Company, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
NITRITE worst: 2013 | 4.9 mg/L 4.9× | 1 mg/L | '12'13 |
NITRATE worst: 2017 | 14 mg/L 1.4× | 10 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE NITRITE worst: 2017 | 12 mg/L 1.2× | 10 mg/L | '17 |
TTHM worst: 2019 | 0.077 mg/L 96% | 0.08 mg/L | '12'13'14'15'16'17'18'19 |
DBCP worst: 2012 | 0.00016 mg/L 80% below national p90 | 0.0002 mg/L | '12'13'14'15'16'17'18'19 |
HAA5 worst: 2015 | 0.043 mg/L within | 0.06 mg/L | '12'13'14'15'16'17'18'19 |
EDB worst: 2018 | 0.000021 mg/L within | 0.00005 mg/L | '18 |
ARSENIC worst: 2013 | 0.0024 mg/L within below national p90 | 0.01 mg/L | '13'17 |
FLUORIDE worst: 2012 | 0.5 mg/L within | 4 mg/L | '12'13'14'15'17 |
CHROMIUM worst: 2013 | 0.0088 mg/L within near national p90 | 0.1 mg/L | '12'13'14'15'17 |
BARIUM worst: 2013 | 0.14 mg/L within near national p90 | 2 mg/L | '13'14'15'17'19 |
DBAA worst: 2012 | 0.0059 mg/L | — | '12'13'14'15'16'17'18'19 |
DCAA worst: 2012 | 0.0041 mg/L | — | '12'13'14'15'16'17'18'19 |
MBAA worst: 2012 | 0.0018 mg/L | — | '12'13'14'15'16'18'19 |
MCAA worst: 2012 | 0.004 mg/L | — | '12'14'15'17'19 |
TCAA worst: 2012 | 0.0031 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMODICHLOROMETHANE worst: 2012 | 0.023 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMOFORM worst: 2012 | 0.013 mg/L | — | '12'13'14'15'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.014 mg/L | — | '12'13'14'15'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.025 mg/L | — | '12'13'14'15'16'17'18'19 |
PWSID CA3610034 · Source: EPA Six-Year Review 4 (2012–2019). Values are the highest detection in each calendar year; non-detect years are omitted. Year tags above show every year with a detection.
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 1.9621212121212122 UG/LAverageSource water | 6 UG/LMCL | Within the limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 360.5882352941176 UMHO/CMAverageSource water | 1600 UMHO/CMMCL | Within the limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 222.94117647058823 MG/LAverageSource water | 1000 MG/LMCL | Within the limit |
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.06411764705882353 NTUAverageSource water | 5 NTUMCL | Within the limit |
| ColorA measure of visible tint in the water. | Not detected UNITSHighest single sampleSource water | 15 UNITSMCL | None detected |
| OdorA measure of detectable smell in the water. | Not detected TONHighest single sampleSource water | 3 TONMCL | None detected |
| AlkalinityA measure of the water's capacity to neutralize acids. | 102.40196078431373 MG/LAverageSource water | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 135.11764705882354 MG/LAverageSource water | None set | Detected — no federal limit |
| pHA measure of how acidic or basic the water is. | 7.852941176470588 PHAverageSource water | None set | Detected — no federal limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Tce | 0.26588235294117646 UG/LAverageSource water | 5 UG/LMCL | Within the limit |
| Carbofuran | Not detected UG/LHighest single sampleSource water | 18 UG/LMCL | None detected |
| Carbon Tetrachloride | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Chlordane | Not detected UG/LHighest single sampleSource water | 0.1 UG/LMCL | None detected |
| Chlorobenzene | Not detected UG/LHighest single sampleSource water | 70 UG/LMCL | None detected |
| Cis Dichloroethylene 12 | Not detected UG/LHighest single sampleSource water | 6 UG/LMCL | None detected |
| Deha | Not detected UG/LHighest single sampleSource water | 400 UG/LMCL | None detected |
| Dehp | Not detected UG/LHighest single sampleSource water | 4 UG/LMCL | None detected |
| Dichloroethane 12 | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Dichloroethylene 11 | Not detected UG/LHighest single sampleSource water | 6 UG/LMCL | None detected |
| Dichloropropane 12 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Dinoseb | Not detected UG/LHighest single sampleSource water | 7 UG/LMCL | None detected |
| Diquat | Not detected UG/LHighest single sampleSource water | 20 UG/LMCL | None detected |
| Endothall | Not detected UG/LHighest single sampleSource water | 100 UG/LMCL | None detected |
| Endrin | Not detected UG/LHighest single sampleSource water | 2 UG/LMCL | None detected |
| Glyphosate | Not detected UG/LHighest single sampleSource water | 700 UG/LMCL | None detected |
| Heptachlor | Not detected UG/LHighest single sampleSource water | 0.01 UG/LMCL | None detected |
| Heptachlor Epoxide | Not detected UG/LHighest single sampleSource water | 0.01 UG/LMCL | None detected |
| Hexachlorobenzene | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Hexachlorocyclopentadiene | Not detected UG/LHighest single sampleSource water | 50 UG/LMCL | None detected |
| Methoxychlor | Not detected UG/LHighest single sampleSource water | 30 UG/LMCL | None detected |
| O Dichlorobenzene | Not detected UG/LHighest single sampleSource water | 600 UG/LMCL | None detected |
| Oxamyl | Not detected UG/LHighest single sampleSource water | 50 UG/LMCL | None detected |
| P Dichlorobenzene | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Pcb Total | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Pce | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Pentachlorophenol | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Picloram | Not detected UG/LHighest single sampleSource water | 500 UG/LMCL | None detected |
| Styrene | Not detected UG/LHighest single sampleSource water | 100 UG/LMCL | None detected |
| Toxaphene | Not detected UG/LHighest single sampleSource water | 3 UG/LMCL | None detected |
| Trans Dichloroethylene 12 | Not detected UG/LHighest single sampleSource water | 10 UG/LMCL | None detected |
| Trichlorobenzene 124 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Trichloroethane 111 | Not detected UG/LHighest single sampleSource water | 200 UG/LMCL | None detected |
| Trichloroethane 112 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Twofourd | Not detected UG/LHighest single sampleSource water | 70 UG/LMCL | None detected |
| Vinyl Chloride | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| SulfateA naturally occurring mineral from rock and soil. | 15.7 MG/LAverageSource water | 500 MG/LMCL | Within the limit |
| ChlorideA naturally occurring salt compound. | 10.1 MG/LAverageSource water | 500 MG/LMCL | Within the limit |
| Cyanide | Not detected UG/LHighest single sampleSource water | 150 UG/LMCL | None detected |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AluminumA common element sometimes used as a treatment coagulant. | Not detected UG/LHighest single sampleSource water | 1000 UG/LMCL | None detected |
| Antimony | Not detected UG/LHighest single sampleSource water | 6 UG/LMCL | None detected |
| Beryllium | Not detected UG/LHighest single sampleSource water | 4 UG/LMCL | None detected |
| Cadmium | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| CopperA metal that enters water from corroding household plumbing. | Not detected UG/LHighest single sampleSource water | 1000 UG/LMCL | None detected |
| IronA naturally occurring metal common in groundwater. | Not detected UG/LHighest single sampleSource water | 300 UG/LMCL | None detected |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected UG/LHighest single sampleSource water | None set | None detected |
| ManganeseA naturally occurring metal from soil and rock. | Not detected UG/LHighest single sampleSource water | 50 UG/LMCL | None detected |
| MercuryA toxic metal from erosion of natural deposits and industrial runoff. | Not detected UG/LHighest single sampleSource water | 2 UG/LMCL | None detected |
| NickelA metal from natural deposits and industrial discharge. | Not detected UG/LHighest single sampleSource water | 100 UG/LMCL | None detected |
| SeleniumA trace element from natural deposits and industrial discharge. | Not detected UG/LHighest single sampleSource water | 50 UG/LMCL | None detected |
| Thallium | Not detected UG/LHighest single sampleSource water | 2 UG/LMCL | None detected |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | Not detected UG/LHighest single sampleSource water | 5000 UG/LMCL | None detected |
| CalciumA naturally occurring mineral that contributes to water hardness. | 22.102941176470587 MG/LAverageSource water | None set | Detected — no federal limit |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 3.6999999999999997 UG/LAverageSource water | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 7.6 MG/LAverageSource water | None set | Detected — no federal limit |
| PotassiumA naturally occurring mineral from rock and soil. | 1.723529411764706 MG/LAverageSource water | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 21.176470588235293 MG/LAverageSource water | None set | Detected — no federal limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 4:2 Fluorotelomer sulfonic acid (4:2 FTS)4:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 6:2 Fluorotelomer sulfonic acid (6:2 FTS)6:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 8:2 Fluorotelomer sulfonic acid (8:2 FTS)8:2 fluorotelomer sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-3-methoxypropanoic acid (PFMPA)Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro-4-methoxybutanoic acid (PFMBA)Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorodecanoic acid (PFDA)Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorododecanoic acid (PFDoA)Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoropentanesulfonic acid (PFPeS)Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
| Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleSource water | None set | None detected |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 1,2,3-TCP | Not detected UG/LHighest single sampleSource water | 0.005 UG/LMCL | None detected |
| AtrazineA widely used agricultural herbicide that reaches water through runoff. | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Benzene | Not detected UG/LHighest single sampleSource water | 1 UG/LMCL | None detected |
| Benzo(a)pyrene | Not detected UG/LHighest single sampleSource water | 0.2 UG/LMCL | None detected |
| ChloroethaneA volatile organic compound used in some industrial processes. | Not detected UG/LHighest single sampleSource water | None set | None detected |
| Chloromethane | Not detected UG/LHighest single sampleSource water | None set | None detected |
| Dalapon | Not detected UG/LHighest single sampleSource water | 200 UG/LMCL | None detected |
| Dichlorodifluoromethane | Not detected UG/LHighest single sampleSource water | None set | None detected |
| Dichloromethane | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Ethylbenzene | Not detected UG/LHighest single sampleSource water | 300 UG/LMCL | None detected |
| Simazine | Not detected UG/LHighest single sampleSource water | 4 UG/LMCL | None detected |
| Toluene | Not detected UG/LHighest single sampleSource water | 150 UG/LMCL | None detected |
| XylenesA group of industrial solvents found in gasoline and paint. | Not detected UG/LHighest single sampleSource water | 1750 UG/LMCL | None detected |
Source: Ontario Municipal Utilities Company, CA's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. utility is required to publish. The numbers on this page are the utility's own. A water-quality report covers an entire service area, not a single address.
People also ask about Ontario Municipal Utilities Company, CA's water
+Is Ontario Municipal Utilities Company, CA tap water safe to drink in 2023?
The 2023 Consumer Confidence Report for the Ontario Municipal Utilities Company, CA water utility lists 2 contaminants at or above the federal limit: PFOA and PFOS. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Ontario Municipal Utilities Company, CA tap water?
121 contaminants were measured in Ontario Municipal Utilities Company, CA's 2023 Consumer Confidence Report, spanning other, pfas ("forever chemicals"), and metals. 80 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Ontario Municipal Utilities Company, CA tap water?
2 contaminants in Ontario Municipal Utilities Company, CA's 2023 report sit at or above the federal limit: PFOA (7.5× the limit); PFOS (1.3× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Ontario Municipal Utilities Company, CA tap water?
The contaminant with the highest measured value relative to its federal limit in the 2023 report is PFOA, at 7.5× the federal threshold. It belongs to the pfas ("forever chemicals") family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Ontario Municipal Utilities Company, CA's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Ontario Municipal Utilities Company, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2023 report; a new report will replace it once the utility publishes its next annual update.
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