Drinking water quality · 2025
· Verified
What's in Pomona - City, Water Dept., CA tap water
103 contaminants were measured in the Pomona - City, Water Dept., CA water system's 2025 annual report. Each is shown below against its federal limit — 5 sit at or above that limit.
- Reporting year
- 2025
- Contaminants measured
- 103
- Over federal limit
- 5
- Approaching the limit
- 2
- Worst contaminant
- Chromium, Hexavalent
- Service area
- CA
1.2× the limit
state-level CCR
At or above the federal limit
- Chromium, HexavalentMetals · Average12.439142857142857 UG/Llimit 10 UG/L · 1.2× the limit
- NitrateInorganic chemicals · Average11.941507936507938 MG/Llimit 10 MG/L · 1.2× the limit
- 1,2,3-TCPVOCs & pesticides · Average0.005956470588235294 UG/Llimit 0.005 UG/L · 1.2× the limit
- Nitrate NitriteOther · Average10.988461538461538 MG/Llimit 10 MG/L · 1.1× the limit
- PerchlorateDisinfection byproducts · Average6.329508196721312 UG/Llimit 6 UG/L · 1.1× the limit
Approaching the limit (≥ 80%)
PFAS — EPA UCMR5 (2023–2025)
2 PFAS compounds above EPA limits in Pomona - City, Water Dept., 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.
PFOS (Perfluorooctane sulfonic acid)
● Over EPA limit (4.5×)Measured 18 ng/LEPA limit 4 ng/LSample year 2024Samples 1 detect / 15
near national p90 (19.900000000000006 ng/L across detecting U.S. systems)
PFOA (Perfluorooctanoic acid)
● Over EPA limit (1.8×)Measured 7.1 ng/LEPA limit 4 ng/LSample year 2024Samples 1 detect / 15
near national p90 (13.649999999999999 ng/L across detecting U.S. systems)
PFHxS (Perfluorohexane sulfonic acid)
● Below limitMeasured 7.9 ng/LEPA limit 10 ng/LSample year 2024Samples 1 detect / 15
near national p90 (12.049999999999997 ng/L across detecting U.S. systems)
PFPeA
● Detected (no federal limit)Measured 4.4 ng/LSample year 2024Samples 1 detect / 15
below national p90 (15.95999999999999 ng/L across detecting U.S. systems)
PFBS
● Detected (no federal limit)Measured 3.2 ng/LSample year 2024Samples 1 detect / 15
below national p90 (13.909999999999979 ng/L across detecting U.S. systems)
Lithium
● Detected (no federal limit)Measured 9.3 mg/LSample year 2023Samples 1 detect / 15
below national p90 (76.59999999999991 mg/L across detecting U.S. systems)
PFHxA
● Detected (no federal limit)Measured 4.1 ng/LSample year 2024Samples 1 detect / 15
below national p90 (12.190000000000003 ng/L across detecting U.S. systems)
PWSID CA1910126 · 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
Pomona - City, Water Dept., CA's drinking water comes from ground water, drawn from 23 sources.
Source
23ground water
- WELL · 18
- TUNNEL · 4
- PEDLEY FILTRATION PLANT - RAW
Treatment
18treatment plants
- WELL 03 AIR STRIPPER
- PEDLEY FILTRATION PLANT - TREATED
- ANION EXCHANGE PLANT - 3
- + 15 more
Distribution
22storage units
Also buys water from METROPOLITAN WATER DIST. OF SO. CAL., THREE VALLEYS MWD.
Source: EPA SDWIS facilities inventory. Methodology.
Historical readings · EPA Six-Year Review (2012–2019)
7 contaminants historically over EPA limits in Pomona - City, Water Dept., 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) |
|---|---|---|---|
TCE worst: 2017 | 0.13 mg/L 26.0× | 0.005 mg/L | '12'13'14'15'16'17'18'19 |
DICHLOROETHYLENE 11 worst: 2012 | 0.061 mg/L 8.7× 7.4× the national p90 | 0.007 mg/L | '12'13'14'15'16'17'18'19 |
PCE worst: 2014 | 0.034 mg/L 6.8× | 0.005 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE worst: 2016 | 29 mg/L 2.9× | 10 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE NITRITE worst: 2018 | 22 mg/L 2.2× | 10 mg/L | '16'17'18'19 |
CHROMIUM worst: 2017 | 0.18 mg/L 1.8× 18.0× the national p90 | 0.1 mg/L | '12'13'14'15'16'17'18'19 |
ARSENIC worst: 2015 | 0.011 mg/L 1.1× near national p90 | 0.01 mg/L | '12'13'14'15'16'17'18 |
TTHM worst: 2012 | 0.051 mg/L within | 0.08 mg/L | '12'13'14'15'16'17'18'19 |
THALLIUM worst: 2015 | 0.0012 mg/L within | 0.002 mg/L | '15 |
DBCP worst: 2018 | 0.00011 mg/L within below national p90 | 0.0002 mg/L | '12'15'18 |
HAA5 worst: 2017 | 0.027 mg/L within | 0.06 mg/L | '12'13'14'15'16'17'18'19 |
FLUORIDE worst: 2013 | 0.6 mg/L within | 4 mg/L | '12'13'14'15'16'17'18'19 |
SELENIUM worst: 2018 | 0.0072 mg/L within | 0.05 mg/L | '14'15'18 |
BARIUM worst: 2012 | 0.1 mg/L within below national p90 | 2 mg/L | '12'13'16'18 |
URANIUM worst: 2018 | 0.007 ug/L within below national p90 | 30 ug/L | '12'13'14'15'16'18'19 |
DBAA worst: 2012 | 0.0034 mg/L | — | '12'13'14'15'16'17'18'19 |
DCAA worst: 2012 | 0.0072 mg/L | — | '12'13'14'15'16'17'18'19 |
MBAA worst: 2016 | 0.0024 mg/L | — | '16'17'18 |
TCAA worst: 2012 | 0.0058 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMODICHLOROMETHANE worst: 2012 | 0.013 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMOFORM worst: 2012 | 0.017 mg/L | — | '12'13'14'15'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.015 mg/L | — | '12'13'14'15'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.019 mg/L | — | '12'13'14'15'16'17'18'19 |
PWSID CA1910126 · 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.
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 12.439142857142857 UG/LAverageSource water | 10 UG/LMCL | At or above the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 2.14 UG/L90th percentileDistribution | 15 UG/LAl | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | 113.57142857142857 UG/LAverageEntry point | 1000 UG/LMCL | Within the limit |
| IronA naturally occurring metal common in groundwater. | 24.8 UG/LAverageSource water | 300 UG/LMCL | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 64.39999999999999 UG/L90th percentileDistribution | 1300 UG/LAl | Within the limit |
| ManganeseA naturally occurring metal from soil and rock. | 1.54 UG/LAverageSource water | 50 UG/LMCL | Within the limit |
| NickelA metal from natural deposits and industrial discharge. | 1.94 UG/LAverageSource water | 100 UG/LMCL | Within the limit |
| ZincA naturally occurring metal that can also enter water from corroding pipes. | 3.35 UG/LAverageEntry point | 5000 UG/LMCL | Within the limit |
| 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 sampleEntry point | 5 UG/LMCL | None detected |
| MercuryA toxic metal from erosion of natural deposits and industrial runoff. | Not detected UG/LHighest single sampleEntry point | 2 UG/LMCL | None detected |
| CalciumA naturally occurring mineral that contributes to water hardness. | 21.782258064516128 MG/LAverageEntry point | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 14.4 MG/LAverageSource water | None set | Detected — no federal limit |
| PotassiumA naturally occurring mineral from rock and soil. | 2.12 MG/LAverageSource water | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 21.39 MG/LAverageEntry point | None set | Detected — no federal limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| 1,2,3-TCP | 0.005956470588235294 UG/LAverageSource water | 0.005 UG/LMCL | At or above the limit |
| Benzene | Not detected UG/LHighest single sampleSource water | 1 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 |
| Dichlorodifluoromethane | Not detected UG/LHighest single sampleEntry point | 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 |
| Toluene | Not detected UG/LHighest single sampleEntry point | 150 UG/LMCL | None detected |
| XylenesA group of industrial solvents found in gasoline and paint. | Not detected UG/LHighest single sampleEntry point | 1750 UG/LMCL | None detected |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 6.329508196721312 UG/LAverageSource water | 6 UG/LMCL | At or above the limit |
| NDMA | Not detected UG/LHighest single sampleEntry point | None set | None detected |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 604.1860465116279 UMHO/CMAverageEntry point | 1600 UMHO/CMMCL | Within the limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 349 MG/LAverageEntry point | 1000 MG/LMCL | Within the limit |
| OdorA measure of detectable smell in the water. | 0.6 TONAverageSource water | 3 TONMCL | Within the limit |
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.3566666666666667 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 |
| AlkalinityA measure of the water's capacity to neutralize acids. | 110.05833333333334 MG/LAverageSource water | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 220 MG/LAverageSource water | None set | Detected — no federal limit |
| pHA measure of how acidic or basic the water is. | 7.968571428571429 PHAverageSource water | None set | Detected — no federal limit |
| TemperatureThe measured temperature of the water sample. | 26.6 CAverageSource water | None set | Detected — no federal limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | 2.66 PCI/LAverageSource water | 15 PCI/LMCL | Within the limit |
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | Not detected PCI/LHighest single sampleSource water | None set | None detected |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorideA naturally occurring salt compound. | 73.77692307692308 MG/LAverageEntry point | 500 MG/LMCL | Within the limit |
| SulfateA naturally occurring mineral from rock and soil. | 47.833333333333336 MG/LAverageSource water | 500 MG/LMCL | Within the limit |
| Cyanide | 3.28 UG/LAverageSource water | 150 UG/LMCL | Within the limit |
| Asbestos | Not detected MFLHighest single sampleSource water | 7 MFLMCL | None detected |
| NitriteA compound from fertilizer runoff, sewage, and erosion of natural deposits. | Not detected MG/LHighest single sampleOther | 1 MG/LMCL | None detected |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Carbon Tetrachloride | Not detected UG/LHighest single sampleEntry point | 0.5 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 |
| Dichloroethane 12 | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
| Dichloropropane 12 | Not detected UG/LHighest single sampleSource water | 5 UG/LMCL | None detected |
| Mcaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| O Dichlorobenzene | Not detected UG/LHighest single sampleEntry point | 600 UG/LMCL | None detected |
| P Dichlorobenzene | Not detected UG/LHighest single sampleEntry point | 5 UG/LMCL | None detected |
| Styrene | Not detected UG/LHighest single sampleSource water | 100 UG/LMCL | None detected |
| Trans Dichloroethylene 12 | Not detected UG/LHighest single sampleEntry point | 10 UG/LMCL | None detected |
| Trichlorobenzene 124 | Not detected UG/LHighest single sampleEntry point | 5 UG/LMCL | None detected |
| Trichloroethane 111 | Not detected UG/LHighest single sampleEntry point | 200 UG/LMCL | None detected |
| Trichloroethane 112 | Not detected UG/LHighest single sampleEntry point | 5 UG/LMCL | None detected |
| Vinyl Chloride | Not detected UG/LHighest single sampleSource water | 0.5 UG/LMCL | None detected |
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 sampleEntry point | None set | None detected |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)ADONA, a newer-generation PFAS replacement compound. | Not detected NG/LHighest single sampleEntry point | 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 sampleEntry point | 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 sampleEntry point | None set | None detected |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)N-ethyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)N-methyl perfluorooctanesulfonamidoacetic acid, a PFAS-related compound. | Not detected NG/LHighest single sampleEntry point | 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 sampleEntry point | 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 sampleEntry point | None set | None detected |
| Perfluoroheptanesulfonic acid (PFHpS)Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | 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 |
| Perfluorotetradecanoic acid (PFTeDA)Perfluorotetradecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluorotridecanoic acid (PFTrDA)Perfluorotridecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluoroundecanoic acid (PFUnA)Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' | Not detected NG/LHighest single sampleEntry point | None set | None detected |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | 1.146969696969697 NG/LAverageSource water | None set | Detected — no federal limit |
| PFBAPerfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' | 1.07765625 NG/LAverageSource water | None set | Detected — no federal limit |
Source: Pomona - City, Water Dept., CA's 2025 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 Pomona - City, Water Dept., CA's water
+Is Pomona - City, Water Dept., CA tap water safe to drink in 2025?
The 2025 Consumer Confidence Report for the Pomona - City, Water Dept., CA water utility lists 5 contaminants at or above the federal limit: Chromium, Hexavalent, Nitrate, 1,2,3-TCP, Nitrate Nitrite, and Perchlorate. 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 Pomona - City, Water Dept., CA tap water?
103 contaminants were measured in Pomona - City, Water Dept., CA's 2025 Consumer Confidence Report, spanning pfas ("forever chemicals"), other, and metals. 57 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 Pomona - City, Water Dept., CA tap water?
5 contaminants in Pomona - City, Water Dept., CA's 2025 report sit at or above the federal limit: Chromium, Hexavalent (1.2× the limit); Nitrate (1.2× the limit); 1,2,3-TCP (1.2× the limit); Nitrate Nitrite (1.1× the limit); Perchlorate (1.1× 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 Pomona - City, Water Dept., CA tap water?
The contaminant with the highest measured value relative to its federal limit in the 2025 report is Chromium, Hexavalent, at 1.2× the federal threshold. It belongs to the metals family of contaminants.
+Are any contaminants in Pomona - City, Water Dept., CA tap water approaching the federal limit?
2 contaminants are between 80% and 100% of the federal limit in this report: Tce and Dichloroethylene 11. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from Pomona - City, Water Dept., CA's 2025 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 Pomona - City, Water Dept., 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 2025 report; a new report will replace it once the utility publishes its next annual update.
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