Is Lathrop Tap Water Safe to Drink?
Short answer: In the 2022–2024 records we hold for Lathrop, PFOS had a sample above a 2024 EPA limit (not a violation: the limit is judged on a yearly average, due 2029). Everything else measured is within its reference or not detected. 3 substances were detected and 28 were tested and not detected. The water is from City of Lathrop, serving 38,596 residents.
- Year 2026
- Utility City of Lathrop
- Coverage 31 records
- Updated 2026-10-15
Where Lathrop’s water comes from
- Utility
- City of Lathrop
- Water system
- CITY OF LATHROP · CA3910015
- Source water
- Surface water
- Disinfectant
- not on record
- Population served
- 38,596
- Reporting period
- Sampled 2022–2024
- Monitoring coverage
- 31 records · 3 of 4 groups measured
EPA lists this system for the city. Your water bill or annual water quality report names your actual supplier. Source: EPA SDWIS 2026Q2.
- CITY OF LATHROPThis reportCA3910015 · 38,596 served
- 1Source
Surface water
- 2Treatment
The treatment details are not on record.
- 3Distribution
Mains, then your building’s service line.
- 4Your tap
Plumbing inside the building is outside this record.
Lathrop water in four numbers
PFOS had a sample above a 2024 EPA limit (not a violation: the limit is judged on a yearly average, due 2029); everything else measured is within its reference or not detected.
3 detected results, by distance from their limit
Each bar runs to the named reference; the tick marks it. Open a row for five layers: measured, compared, meaning, where it matters, what to do.Perfluorooctanesulfonic acid (PFOS)Above EPA's 2024 limit (one sample) · Federal MCL4.0 ng/L federal MCL (2024)17ng/L
17 ng/L, sampled 2024-01-16 to 2024-10-14. 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)).
Perfluorohexanesulfonic acid (PFHxS)Within reference · Federal MCL10 ng/L federal MCL (2024)3.5ng/L
3.5 ng/L, sampled 2024-01-16 to 2024-10-14. 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 3.5 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).
Perfluorobutanesulfonic acid (PFBS)Within reference · Screening level2,000 ng/L EPA health advisory (screening, not a legal limit)5ng/L
5 ng/L, sampled 2024-01-16 to 2024-10-14. EPA UCMR 5.
2,000 ng/L EPA health advisory (screening, not a legal limit).
Detected at up to 5.0 ng/L (below the 2,000 ng/L EPA health advisory; a screening level, not a legal limit).
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 PFBS named on the listing).
28 others tested, none detectedshow
- 11Cl-PF3OUdS
- 8:2 FTS
- 4:2 FTS
- 6:2 FTS
- ADONA
- 9Cl-PF3ONS
- HFPO-DA (GenX)
- Lead (90th percentile)
- Lithium
- NEtFOSAA
- NMeFOSAA
- NFDHA
- PFEESA
- PFMPA
- PFMBA
- PFBA
- PFDA
- PFDoA
- PFHpS
- PFHpA
- PFHxA
- PFNA
- PFOA
- PFPeS
- PFPeA
- PFTA
- PFTrDA
- PFUnA
CITY OF LATHROP (EPA PWSID CA3910015) delivers surface water to 38,596 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.
Your tap can differ from the city record
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 water- CityTreated water
Measured in this report
- MainsDistribution network
Sampled across the system
- BuildingService line and plumbing
Not in this record
- TapYour glass
Only a tap test measures it
Water testing in Lathrop, CA
- 01Test
Know what comes from your tap, starting with a first-draw lead sample.
- 02Match
Compare each result with its named reference in our test reader.
- 03Treat
Choose a technology certified for what your test found.
How to test your tap water at home →
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 →
What can reduce what was found here
Finding → technology → certification → product, in that order. The reference type carries the meaning; there is no severity score.| Finding | Reference type | Technology | Certification to check |
|---|---|---|---|
| Perfluorooctanesulfonic acid (PFOS)17 ng/L | Federal MCL | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58 (PFOA/PFOS) |
| Perfluorohexanesulfonic acid (PFHxS)3.5 ng/L | Federal MCL | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58, with PFHxS named on the listing |
| Perfluorobutanesulfonic acid (PFBS)5 ng/L | Screening level | Reverse osmosis, or carbon certified for PFAS | NSF/ANSI 53 or 58, with PFBS named on the listing |
Filters for the PFAS found in Lathrop water
Affiliate linksPurityMap 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★ Best choice: Aquasana Claryum 2-Stage Under-Sink Filter (AQ-5200), certified for PFOS.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best choice | Under-sinkAquasana Claryum 2-Stage Under-Sink Filter (AQ-5200) | TreatsPFOSPrice$$ | Certified for PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price on Amazon |
| Also good | Under-sinkAquasana Claryum 3-Stage Max Flow Under-Sink Filter (AQ-6300M) | TreatsPFOSPrice$$ | Certified for PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price at Aquasana |
| Also good | CountertopAquasana Clean Water Machine Countertop Filter (AQ-CWM2) | TreatsPFOSPrice$$ | Certified for PFOS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price at Aquasana |
See all 12 drinking-water options for PFAS
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| Also good | Reverse osmosisSmartFlow® Reverse Osmosis | TreatsPFOSTechnologyReverse osmosisPrice$$$ | Certified for PFOS (NSF/ANSI 53 (includes P473), WQA) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price at Aquasana |
| Also good | Under-sinkWaterdrop G3P600 Tankless Reverse-Osmosis System | TreatsPFOSPrice$$$ | Certified for PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price at Waterdrop |
| Also good | Under-sinkWaterdrop G3P800 Tankless Reverse-Osmosis System | TreatsPFOSPrice$$$ | Certified for PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price at Waterdrop |
| Also good | CountertopAquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100) | TreatsPFOSPrice$$$ | Certified for PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price on Amazon |
| Also good | CountertopAquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000) | TreatsPFOSPrice$$$ | Certified for PFOS (NSF/ANSI 53, IAPMO) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price on Amazon |
| Also good | CountertopPatriot Pure Ultimate Water Filtration System | TreatsPFOSPrice$$ | Certified for PFOS (NSF/ANSI 53, NSF, IAPMO) | Why it’s listed: its current certification names PFOS, found in Lathrop’s record.See the evidence | Check price on Amazon |
| Also good | Reverse osmosisiSpring RCC7AK Alkaline Reverse Osmosis SystemUse code REFISPRING at checkout: 10% off your first iSpring order. | TechnologyReverse osmosisPrice$$ | Brand lab-tested for PFAS, not independently certified for PFOS, Perfluorobutanesulfonic acid (PFBS) 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$$$ | Brand lab-tested for PFAS, not independently certified for PFOS, Perfluorobutanesulfonic acid (PFBS) and PFHxS | See the evidence | Check price at iSpring |
| Also good | Reverse osmosisWaterdrop X12 Reverse Osmosis System | TechnologyReverse osmosisPrice$$$$ | Brand lab-tested for PFAS, not independently certified for PFOS, Perfluorobutanesulfonic acid (PFBS) and PFHxS | See the evidence | Check price at Waterdrop |
★ Best choice: HealthShield™, certified for PFOS and PFHxS.
| Pick | Product | Details and price | Certification | Why it’s listed | Link |
|---|---|---|---|---|---|
| ★ Best choice | Whole-houseHealthShield™ | TreatsPFOS and PFHxSPrice$$$$ | Certified for PFOS and PFHxS (NSF/ANSI 53, WQA) | Why it’s listed: its current certification names PFOS and PFHxS, found in Lathrop’s record.See the evidence | Check price at Aquasana |
| $ Budget pick | Whole-houseiSpring WGB32B-PFKS PFAS & Heavy Metals Whole House FilterUse code REFISPRING at checkout: 10% off your first iSpring order. | Price$$$ | Brand lab-tested for PFAS, not independently certified for PFOS, Perfluorobutanesulfonic acid (PFBS) and PFHxS | See the evidence | Check price at iSpring |
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.
Choose your situation
Older buildings may have lead service lines, solder or fixtures. Lead is not in Lathrop’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 Lathrop’s record (PFOS 17 ng/L, PFHxS 3.5 ng/L and PFBS 5 ng/L); 1 above its 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.
Lathrop tap water FAQ
Get one email when Lathrop’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.Is Lathrop tap water safe to drink?
PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For Lathrop, PFOS 17 ng/L was measured in one EPA sample, above the 4 ng/L limit EPA set in 2024 (not a violation: the limit is judged on a yearly average, due 2029). CITY OF LATHROP (PWSID CA3910015) 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 →
Who provides tap water in Lathrop?
CITY OF LATHROP (PWS ID CA3910015) is the public water system on record for Lathrop, California, serving about 38,596 people. Confirm the utility on your water bill before acting on a specific finding. Water utility →
Where does Lathrop get its drinking water?
Surface water (primary source of record in EPA SDWIS). Water utility →
Are PFAS "forever chemicals" in Lathrop's water?
Yes. In EPA's UCMR 5 testing (2024-01-16 to 2024-10-14), PFOS was measured at 17 ng/L in one EPA sample, 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. PFBS (5 ng/L, below the 2,000 ng/L EPA health advisory) and PFHxS (3.5 ng/L, below the 10 ng/L federal limit) were also detected. Reverse osmosis and filters certified to NSF/ANSI 53 for PFOA/PFOS reduce them at the tap. What we found →
Is there lead in Lathrop's tap water?
Lead is not in Lathrop'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 →
What does the latest Lathrop water report show?
PurityMap's current record for Lathrop holds 31 findings: 1 above a reference, 2 detected within the reference and 28 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 →
31 records, each traceable
- EPA UCMR 5
- EPA SDWIS (Lead & Copper Rule)
UCMR5 Analytical Results
UCMR5 Analytical Results: CITY OF LATHROP (CA3910015)
US EPA
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: CITY OF LATHROP (CA3910015)
US EPA SDWIS
Methodology: how we analyze water. Prepared with AI assistance and reviewed by the PurityMap Editorial Team before publication.
How PurityMap reads Lathrop’s water
- 01Source data
EPA SDWIS, EPA UCMR 5 and utility reports, each dated and linked.
- 02Normalize
Units converted to one basis; a non-detect kept distinct from zero.
- 03Classify
Each result tagged by reference type: MCL, action level, screening level or aesthetic.
- 04Compare to the named reference
Every value sits against its own reference, never a blended one.
- 05Score
Measured subjects summarised at the water-system level; an open health-based violation caps the score.
- 06Match treatment
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. CITY OF LATHROP · PWSID CA3910015 · Purity Score 57/100 (Fair) · Confidence: moderate · Assessed at the water-system level
Full methodology →Something off with your water's smell, color or taste?
Start with the hot-or-cold tap check. Where City of Lathrop reported something related, it's shown below.
- Rotten-egg smell
- Cloudy or milky water
- Chlorine smell
- Brown or yellow water
- Metallic taste
Lead at City of Lathrop: not detected (90th percentile, 2022–2024 monitoring period). Lead has no taste, so a taste neither shows nor rules it out.