Short answer: In the 2022–2024 records we hold for Compton, two PFAS, PFOA and PFOS, each had a sample above a 2024 EPA limit (not a violation: the limits are judged on a yearly average, due 2029). Also worth knowing: lithium sits above a screening level. 4 substances were detected and 27 were tested and not detected. The water is from Compton-City, Water Dept., serving 90,986 residents.
EPA lists this system for the city. Your water bill or annual water quality report names your actual supplier. Source: EPA SDWIS 2026Q2.
Surface water
The treatment details are not on record.
Mains, then your building’s service line.
Plumbing inside the building is outside this record.
Two PFAS, PFOA and PFOS, each had a sample above a 2024 EPA limit (not a violation: the limits are judged on a yearly average, due 2029); lithium sits above a screening level.
58 µg/L, sampled 2023-09-14 to 2024-05-09. EPA UCMR 5.
10 µg/L EPA health reference level (screening, not a legal limit).
Detected at up to 58 µg/L (above the 10 µg/L EPA health reference level; a screening level, not a legal limit).
Where it enters is not in this record.
Test your own tap first. To reduce it: Depends on the contaminant (The certifier's listing for each named contaminant).
17 ng/L, sampled 2023-09-14 to 2024-05-09. EPA UCMR 5.
4.0 ng/L federal MCL (2024): a legal limit. That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. EPA health goal (MCLG): 0.
One EPA sample measured 17 ng/L, above the 4 ng/L limit EPA set in 2024. That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation.
Comes with the source water; home plumbing does not add it.
Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58 (PFOA/PFOS)).
4.9 ng/L, sampled 2023-09-14 to 2024-05-09. EPA UCMR 5.
4.0 ng/L federal MCL (2024): a legal limit. That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. EPA health goal (MCLG): 0.
One EPA sample measured 4.9 ng/L, above the 4 ng/L limit EPA set in 2024. That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation.
Comes with the source water; home plumbing does not add it.
Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58 (PFOA/PFOS)).
4.1 ng/L, sampled 2023-09-14 to 2024-05-09. EPA UCMR 5.
10 ng/L federal MCL (2024): a legal limit. That limit is judged on a yearly average, and water systems have until 2029 to meet it.
Detected at up to 4.1 ng/L (below the 10 ng/L limit EPA set in 2024). That limit is judged on a yearly average, and water systems have until 2029 to meet it.
Comes with the source water; home plumbing does not add it.
Test your own tap first. To reduce it: Reverse osmosis, or carbon certified for PFAS (NSF/ANSI 53 or 58, with PFHxS named on the listing).
COMPTON-CITY, WATER DEPT. (EPA PWSID CA1910026) delivers surface water to 90,986 residents. This report reflects 29 individual PFAS result(s) from the source UCMR5 observations and the latest Lead & Copper Rule 90th-percentile result. Water hardness and disinfectant type are pending the utility's own annual report.
0health-based violations in the last 10 years
From EPA SDWIS. A clean violation history means no enforcement action was recorded; it does not cover contaminants without a limit.
No result is not a pass. Your utility's annual water quality report may list them, and a certified lab test covers your own tap.
The record describes water leaving treatment and samples across the system. Pipes, solder and fixtures inside a building can add lead the record can’t see, especially in older buildings with lead service lines.
Test your waterMeasured in this report
Sampled across the system
Not in this record
Only a tap test measures it
Know what comes from your tap, starting with a first-draw lead sample.
Compare each result with its named reference in our test reader.
Choose a technology certified for what your test found.
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Screening: quick check, not lab-grade
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.
When your results arrive, read them here → · Compare every kit we list
California State Water Resources Control Board certifies the labs that test drinking water in California. Find a certified lab in California ↗ · What lab tests cost →
| Finding | Reference type | Technology | Certification to check |
|---|---|---|---|
| Lithium58 µg/L | Screening level | Depends on the contaminant | The certifier's listing for each named contaminant |
| Perfluorooctanesulfonic acid (PFOS)17 ng/L | Federal MCL | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58 (PFOA/PFOS) |
| Perfluorooctanoic acid (PFOA)4.9 ng/L | Federal MCL | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58 (PFOA/PFOS) |
| Perfluorohexanesulfonic acid (PFHxS)4.1 ng/L | Federal MCL | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58, with PFHxS named on the listing |
★ Best choice: Aquasana Claryum 2-Stage Under-Sink Filter (AQ-5200), certified for PFOA and PFOS.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best choice | Under-sinkAquasana Claryum 2-Stage Under-Sink Filter (AQ-5200) | TreatsPFOA and PFOSPrice$$ | Certified for PFOA and PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price on Amazon |
| Also good | Under-sinkAquasana Claryum 3-Stage Max Flow Under-Sink Filter (AQ-6300M) | TreatsPFOA and PFOSPrice$$ | Certified for PFOA and PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price at Aquasana |
| Also good | CountertopAquasana Clean Water Machine Countertop Filter (AQ-CWM2) | TreatsPFOA and PFOSPrice$$ | Certified for PFOA and PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price at Aquasana |
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| Also good | Reverse osmosisSmartFlow® Reverse Osmosis | TreatsPFOA and PFOSTechnologyReverse osmosisPrice$$$ | Certified for PFOA and PFOS (NSF/ANSI 53 (includes P473), WQA) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price at Aquasana |
| Also good | Under-sinkWaterdrop G3P600 Tankless Reverse-Osmosis System | TreatsPFOA and PFOSPrice$$$ | Certified for PFOA and PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price at Waterdrop |
| Also good | Under-sinkWaterdrop G3P800 Tankless Reverse-Osmosis System | TreatsPFOA and PFOSPrice$$$ | Certified for PFOA and PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price at Waterdrop |
| Also good | CountertopAquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100) | TreatsPFOA and PFOSPrice$$$ | Certified for PFOA and PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price on Amazon |
| Also good | CountertopAquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000) | TreatsPFOA and PFOSPrice$$$ | Certified for PFOA and PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price on Amazon |
| Also good | CountertopPatriot Pure Ultimate Water Filtration System | TreatsPFOA and PFOSPrice$$ | Certified for PFOA and PFOS (NSF/ANSI 53, NSF, IAPMO) | Why it’s listed: its current certification names PFOA and PFOS, found in Compton’s record.See the evidence | Check price on Amazon |
| Also good | Reverse osmosisiSpring RCC7AK Alkaline Reverse Osmosis SystemUse code REFISPRING at checkout: 10% off your first iSpring order. | TechnologyReverse osmosisPrice$$ | Brand lab-tested for PFAS, not independently certified for PFOA, PFOS and PFHxS | See the evidence | Check price at iSpring |
| Also good | Reverse osmosisiSpring RO5004F Tankless Reverse Osmosis System with UVUse code REFISPRING at checkout: 10% off your first iSpring order. | TechnologyReverse osmosisPrice$$$ | Brand lab-tested for PFAS, not independently certified for PFOA, PFOS and PFHxS | See the evidence | Check price at iSpring |
| Also good | Reverse osmosisWaterdrop X12 Reverse Osmosis System | TechnologyReverse osmosisPrice$$$$ | Brand lab-tested for PFAS, not independently certified for PFOA, PFOS and PFHxS | See the evidence | Check price at Waterdrop |
★ Best choice: HealthShield™, certified for PFOA, PFOS and PFHxS.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best choice | Whole-houseHealthShield™ | TreatsPFOA, PFOS and PFHxSPrice$$$$ | Certified for PFOA, PFOS and PFHxS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOA, PFOS and PFHxS, found in Compton’s record.See the evidence | Check price at Aquasana |
| $ Budget pick | Whole-houseiSpring WGB32B-PFKS PFAS & Heavy Metals Whole House FilterUse code REFISPRING at checkout: 10% off your first iSpring order. | Price$$$ | Brand lab-tested for PFAS, not independently certified for PFOA, PFOS and PFHxS | See the evidence | Check price at iSpring |
Certified filters for lithium →
PurityMap earns a commission from these links. "Best choice" and "Budget pick" go to certified products first; commission never decides them. As an Amazon Associate, PurityMap earns from qualifying purchases. Affiliate disclosure.
Older buildings may have lead service lines, solder or fixtures. Lead is not in Compton’s published record, so only a tap test tells you. Test first-draw water, then filter if needed.
3 of 29 PFAS tested were detected in Compton’s record (PFOS 17 ng/L, PFOA 4.9 ng/L and PFHxS 4.1 ng/L); 2 above their limit. If PFAS matters to you, a filter certification names each compound it covers.
Most utilities keep chlorine or chloramine in the pipes. A carbon filter certified for taste and odor reduces either; your utility can tell you which it uses.
Your utility’s annual water quality report usually lists hardness; a test strip also measures it.
Reverse osmosis reduces many dissolved contaminants, including lead and minerals, at a single faucet, with some water sent to drain.
Get one email when Compton’s record changes.
One email when a new sampling round is published, a result moves above or below its reference, or the system's score changes.PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For Compton, PFOS 17 ng/L and PFOA 4.9 ng/L were measured in one EPA sample each, above the 4 ng/L limit EPA set in 2024 (not a violation: the limits are judged on a yearly average, due 2029). COMPTON-CITY, WATER DEPT. (PWSID CA1910026) has a Purity Score of 57/100 (confidence: moderate), assessed at the water-system level and computed only from contaminants that were measured. Water can change in your own pipes, so a certified test is the only way to know what comes out of your tap. What we found →
COMPTON-CITY, WATER DEPT. (PWS ID CA1910026) is the public water system on record for Compton, California, serving about 90,986 people. Confirm the utility on your water bill before acting on a specific finding. Water utility →
Surface water (primary source of record in EPA SDWIS). Water utility →
Yes. In EPA's UCMR 5 testing (2023-09-14 to 2024-05-09), PFOS was measured at 17 ng/L in one EPA sample, above the 4 ng/L limit EPA set in 2024 and PFOA was measured at 4.9 ng/L in one EPA sample, above the 4 ng/L limit EPA set in 2024. EPA's 2024 limits are judged on a yearly average, and water systems have until 2029 to meet them, so a single sample is not a violation. PFHxS was detected below its limit. Reverse osmosis and filters certified to NSF/ANSI 53 for PFOA/PFOS reduce them at the tap. What we found →
Lead is not in Compton's current published record. Lead usually enters from a building's own pipes and fixtures, so a certified home test is the way to know yours. Your household →
PurityMap's current record for Compton holds 31 findings: 3 above a reference, 1 detected within the reference and 27 not detected. Each finding links to its dated public record; a parameter that was never monitored is shown as pending, not as a pass. Records →
| Contaminant | Measured | Reference | Sampled | Source |
|---|---|---|---|---|
| Lithium | 58 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorooctanesulfonic acid (PFOS) | 17 ng/L | 4.0 ng/L federal MCL (2024) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorooctanoic acid (PFOA) | 4.9 ng/L | 4.0 ng/L federal MCL (2024) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorohexanesulfonic acid (PFHxS) | 4.1 ng/L | 10 ng/L federal MCL (2024) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L (not detected) | 10 ng/L federal MCL (2024) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Lead (90th percentile) | Not detected | 15 µg/L federal action level | 2022–2024 | EPA SDWIS (Lead & Copper Rule) ↗ (opens in a new tab) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L (not detected) | 2,000 ng/L EPA health advisory (screening, not a legal limit) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L (not detected) | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L (not detected) | 10 ng/L federal MCL (2024) | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L (not detected) | No federal or state limit; shown for transparency | 2023–2024 | EPA UCMR 5 ↗ (opens in a new tab) |
UCMR5 Analytical Results
UCMR5 Analytical Results: COMPTON-CITY, WATER DEPT. (CA1910026)
US EPA
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: COMPTON-CITY, WATER DEPT. (CA1910026)
US EPA SDWIS
Methodology: how we analyze water. Prepared with AI assistance and reviewed by the PurityMap Editorial Team before publication.
EPA SDWIS, EPA UCMR 5 and utility reports, each dated and linked.
Units converted to one basis; a non-detect kept distinct from zero.
Each result tagged by reference type: MCL, action level, screening level or aesthetic.
Every value sits against its own reference, never a blended one.
Measured subjects summarised at the water-system level; an open health-based violation caps the score.
Treatment is matched to what was found; a product is called certified only when its current certification names it.
What the Purity Score means: a summary of this water system’s published record, capped while a health-based violation is open. It is not a test of any tap. COMPTON-CITY, WATER DEPT. · PWSID CA1910026 · Purity Score 57/100 (Fair) · Confidence: moderate · Assessed at the water-system level
Full methodology →Start with the hot-or-cold tap check. Where Compton-City, Water Dept. reported something related, it's shown below.
Lead at Compton-City, Water Dept.: not detected (90th percentile, 2022–2024 monitoring period). Lead has no taste, so a taste neither shows nor rules it out.