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LOS OSOS COMMUNITY SERVICES DISTRICTlikely match
City water report · 2026

Is Los Osos Tap Water Safe? 2026 Water Quality Report

Short answer: Two PFAS, PFOA and PFOS, are above their federal limits (2024 limits that water systems have until at least 2029 to meet); lithium sits above a screening level. Los Osos Community Services District serves 7,086 residents.

Explore the findingsWhat can I do?Follow
Likely match, check your bill

LOS OSOS COMMUNITY SERVICES DISTRICT serves Los Osos

Your water bill or annual water quality report names your actual supplier.

Source
Groundwater
What stands out

Two PFAS above the 2024 federal limit

Each bar is drawn in blocks of the 4.0 ng/L federal MCL (2024), so the length shows how far above it the result sits.

PFOA

Perfluorooctanoic acid

3.7× the limit

14.7ng/L

Each block = 4.0 ng/L federal MCL (2024)

EPA UCMR 5 · sampled 2024Evidence
PFOS

Perfluorooctanesulfonic acid

2.9× the limit

11.7ng/L

Each block = 4.0 ng/L federal MCL (2024)

EPA UCMR 5 · sampled 2024Evidence

Coverage by group

31 results on record
  • PFAS (forever chemicals)2 above · 6 detected · 21 not detected
  • Metals & lead1 detected
  • Disinfection by-productsNot monitored
  • Other1 above
Every detected result

10 detected results, by distance from their limit

LOS OSOS COMMUNITY SERVICES DISTRICT (EPA PWSID CA4010016) delivers groundwater to 7,086 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.

21 other contaminants tested, none detected
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpS
  • PFMBA
  • PFMPA
  • PFNA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA
Track record

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.

Not in this recordDisinfection by-products weren't monitored in this dataset

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.

What you can do

Test first, then treat what was found

  1. 01 · TestTest your own tap

    Plumbing inside a home can add lead that the system record can't show. A tap test tells you what reaches your glass.

    Certified lab
    How to test your tap →
  2. 02 · Treat PFASReverse osmosis, or carbon certified for PFAS

    PFOA 14.7 ng/L, above the 4 ng/L limit (+7 more PFAS detected)

    NSF/ANSI 58 or 53, with PFOA/PFOS/PFBS/PFHxA/PFHxS/PFBA/PFHpA/PFPeA named on the listing
    Treatment for PFAS →
  3. 03 · LeadLead-certified carbon filter, or reverse osmosis

    lead 1.1 µg/L, below the 15 µg/L action level

    NSF/ANSI 53 (lead)
    Treatment for Lead →

Understand water treatment technologies →

Test your own tap

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.

  • Screening: quick check, not lab-grade

    Safe Home DIY Lead in Drinking Water Combo Test Kit

    Safe Home (EnviroTestKits)

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  • Lab-certified results

    ETR Labs Basic Water Quality Test Kit

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    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.

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When your results arrive, read them here →

Commercial

Certified for a concern found here

Each card names which Los Osos findings its current certification covers, and which it doesn't.

As an Amazon Associate, PurityMap earns from qualifying purchases. A product appears here only when a current certification record covers at least one identified concern; every concern stays listed. The retail offer is looked up afterwards and never changes which products appear or their order. Affiliate disclosure.

Under-Sink Filter

Aquasana Claryum 2-Stage Under-Sink Filter (AQ-5200)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (5)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
  • Anyone who can't plumb, drill or hire an installer
  • Renters who can't modify plumbing
See the evidenceCheck price on Amazon
Under-Sink Filter

Aquasana Claryum 3-Stage Max Flow Under-Sink Filter (AQ-6300M)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (5)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
  • Anyone who can't plumb, drill or hire an installer
  • Renters who can't modify plumbing
See the evidenceCheck price on Amazon
See all 13 products certified for a Los Osos concern →
Countertop System

Aquasana Clean Water Machine Countertop Filter (AQ-CWM2)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Countertop System

Patriot Pure Ultimate Water Filtration System

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Countertop System

AquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Countertop System

AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Under-Sink Filter

Waterdrop G3P600 Tankless Reverse-Osmosis System

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (5)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
  • Anyone who can't plumb, drill or hire an installer
  • Renters who can't modify plumbing
See the evidenceCheck price on Amazon
Under-Sink Filter

Waterdrop G3P800 Tankless Reverse-Osmosis System

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (5)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
  • Anyone who can't plumb, drill or hire an installer
  • Renters who can't modify plumbing
See the evidenceCheck price on Amazon
Refrigerator Filter

Whirlpool Filter 3 Refrigerator Water Filter (WHR3RXD1)

  • PFOA: eligible, evidence match
  • PFOS: eligible, evidence match
  • Lead: eligible, evidence match
  • Not established: Lithium, Perfluorobutanesulfonic acid (PFBS), Perfluorohexanoic acid (PFHxA) and 4 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Water Pitcher

Brita Elite Water Filter Pitcher

  • Lead: eligible, evidence match
  • Not established: PFOA, PFOS, Lithium and 6 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Water Pitcher

Culligan ZeroWater 10-Cup Pitcher (ZEROP10)

  • Lead: eligible, evidence match
  • Not established: PFOA, PFOS, Lithium and 6 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Faucet Attachment

PUR Plus Faucet Filter (FM2500V)

  • Lead: eligible, evidence match
  • Not established: PFOA, PFOS, Lithium and 6 more
Not suitable for (3)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
See the evidenceCheck price on Amazon
Under-Sink Filter

Frizzlife SP99 Under-Sink Filter

  • Lead: eligible, evidence match
  • Not established: PFOA, PFOS, Lithium and 6 more
Not suitable for (4)
  • Treating every tap in the home
  • A whole-home hard-water or scale problem
  • All PFAS: its evidence covers only the compounds it names
  • Anyone who can't plumb, drill or hire an installer
See the evidenceCheck price on Amazon
Questions

Frequently asked questions

Is Los Osos tap water safe to drink?

PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For Los Osos, PFOA 14.7 ng/L and PFOS 11.7 ng/L were measured above the 4 ng/L federal limit in EPA's 2024 testing; the lead 90th-percentile result was 1.1 µg/L against the 15 µg/L action level. LOS OSOS COMMUNITY SERVICES DISTRICT (PWSID CA4010016) has a Purity Score of 56/100 (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.

Who provides tap water in Los Osos?

LOS OSOS COMMUNITY SERVICES DISTRICT (PWS ID CA4010016) is the public water system on record for Los Osos, California, serving about 7,086 people. Confirm the utility on your water bill before acting on a specific finding.

Where does Los Osos get its drinking water?

Groundwater (primary source of record in EPA SDWIS).

Are PFAS "forever chemicals" in Los Osos's water?

Yes. In EPA's UCMR 5 testing (2024-01-08 to 2024-07-08), PFOA was measured at 14.7 ng/L against a 4 ng/L federal limit and PFOS was measured at 11.7 ng/L against a 4 ng/L federal limit. PFBS (18 ng/L, below the 2,000 ng/L EPA health advisory), PFHxA (16.6 ng/L, below the 400,000 ng/L state limit) and PFHxS (8.4 ng/L, below the 10 ng/L federal limit) were also detected. PFBA (6 ng/L), PFHpA (5.4 ng/L) and PFPeA (16.8 ng/L) were also detected; they have no federal or state limit. Reverse osmosis and filters certified to NSF/ANSI 53 for PFOA/PFOS reduce them at the tap.

Is there lead in Los Osos's tap water?

LOS OSOS COMMUNITY SERVICES DISTRICT's most recent lead 90th-percentile result (2024–2026) was 1.1 µg/L, below the 15 µg/L action level. That figure comes from sampled homes; lead usually enters from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

What does the latest Los Osos water report show?

PurityMap's current record for Los Osos holds 31 findings: 3 above a reference, 4 detected within the reference, 3 detected with no limit and 21 not detected. Each finding links to its dated public record; a parameter that was never monitored is shown as pending, not as a pass.

Follow this water

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Sources and dataAll 31 records and their sourcesEPA UCMR 5 · EPA SDWIS (Lead & Copper Rule)
ContaminantResultBenchmarkStatusSampledSource
Perfluorooctanoic acid (PFOA)14.7 ng/L4.0 ng/L federal MCL (2024)Above a historical reference; current applicability unverified2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorooctanesulfonic acid (PFOS)11.7 ng/L4.0 ng/L federal MCL (2024)Above a historical reference; current applicability unverified2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Lithium16.1 µg/L10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limitAbove the referenced health-based guidance value2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorohexanesulfonic acid (PFHxS)8.4 ng/L10 ng/L federal MCL (2024)Within a historical reference; current applicability unverified2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Lead (90th percentile)1.1 µg/L15 µg/L federal action levelBelow the listed reference2024–2026 monitoring period (still open)Lead & Copper Rule 90th-percentile: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorobutanesulfonic acid (PFBS)18 ng/L2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limitWithin the referenced health-based guidance value2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorohexanoic acid (PFHxA)16.6 ng/L400,000 ng/L Michigan EGLE state MCL (strictest US state)Within a historical reference; current applicability unverified2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorobutanoic acid (PFBA)6 ng/LNo federal or state limit; shown for transparencyDetected, no limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoroheptanoic acid (PFHpA)5.4 ng/LNo federal or state limit; shown for transparencyDetected, no limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoropentanoic acid (PFPeA)16.8 ng/LNo federal or state limit; shown for transparencyDetected, no limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
21 other PFAS tested — none detected
ContaminantResultBenchmarkStatusSampledSource
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)< 5 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)< 5 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)< 5 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)< 2 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)< 5 ng/L10 ng/L federal MCL (2024)Not detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)< 5 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)< 6 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)< 20 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoro-3-methoxypropanoic acid (PFMPA)< 4 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoro-4-methoxybutanoic acid (PFMBA)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorodecanoic acid (PFDA)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorododecanoic acid (PFDoA)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoroheptanesulfonic acid (PFHpS)< 3 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorononanoic acid (PFNA)< 4 ng/L10 ng/L federal MCL (2024)Not detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoropentanesulfonic acid (PFPeS)< 4 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorotetradecanoic acid (PFTA)< 8 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluorotridecanoic acid (PFTrDA)< 7 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)
Perfluoroundecanoic acid (PFUnA)< 2 ng/LNo federal or state limit; shown for transparencyNot detected above the reporting limit2024-01-08 to 2024-07-08UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)

Perfluorooctanoic acid (PFOA)

Result
14.7 ng/L
Benchmark
4.0 ng/L federal MCL (2024)
Status
Above a historical reference; current applicability unverified
Sampled
2024-01-08 to 2024-07-08

Perfluorooctanesulfonic acid (PFOS)

Result
11.7 ng/L
Benchmark
4.0 ng/L federal MCL (2024)
Status
Above a historical reference; current applicability unverified
Sampled
2024-01-08 to 2024-07-08

Lithium

Result
16.1 µg/L
Benchmark
10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit
Status
Above the referenced health-based guidance value
Sampled
2024-01-08 to 2024-07-08

Perfluorohexanesulfonic acid (PFHxS)

Result
8.4 ng/L
Benchmark
10 ng/L federal MCL (2024)
Status
Within a historical reference; current applicability unverified
Sampled
2024-01-08 to 2024-07-08

Lead (90th percentile)

Result
1.1 µg/L
Benchmark
15 µg/L federal action level
Status
Below the listed reference
Sampled
2024–2026 monitoring period (still open)

Perfluorobutanesulfonic acid (PFBS)

Result
18 ng/L
Benchmark
2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit
Status
Within the referenced health-based guidance value
Sampled
2024-01-08 to 2024-07-08

Perfluorohexanoic acid (PFHxA)

Result
16.6 ng/L
Benchmark
400,000 ng/L Michigan EGLE state MCL (strictest US state)
Status
Within a historical reference; current applicability unverified
Sampled
2024-01-08 to 2024-07-08

Perfluorobutanoic acid (PFBA)

Result
6 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Detected, no limit
Sampled
2024-01-08 to 2024-07-08

Perfluoroheptanoic acid (PFHpA)

Result
5.4 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Detected, no limit
Sampled
2024-01-08 to 2024-07-08

Perfluoropentanoic acid (PFPeA)

Result
16.8 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Detected, no limit
Sampled
2024-01-08 to 2024-07-08
21 other PFAS tested — none detected

11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)

Result
< 5 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)

Result
< 5 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)

Result
< 5 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

4,8-Dioxa-3H-perfluorononanoic acid (ADONA)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)

Result
< 2 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)

Result
< 5 ng/L
Benchmark
10 ng/L federal MCL (2024)
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)

Result
< 5 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)

Result
< 6 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)

Result
< 20 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoro-3-methoxypropanoic acid (PFMPA)

Result
< 4 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoro-4-methoxybutanoic acid (PFMBA)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluorodecanoic acid (PFDA)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluorododecanoic acid (PFDoA)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoroheptanesulfonic acid (PFHpS)

Result
< 3 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluorononanoic acid (PFNA)

Result
< 4 ng/L
Benchmark
10 ng/L federal MCL (2024)
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoropentanesulfonic acid (PFPeS)

Result
< 4 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluorotetradecanoic acid (PFTA)

Result
< 8 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluorotridecanoic acid (PFTrDA)

Result
< 7 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Perfluoroundecanoic acid (PFUnA)

Result
< 2 ng/L
Benchmark
No federal or state limit; shown for transparency
Status
Not detected above the reporting limit
Sampled
2024-01-08 to 2024-07-08

Every value is the published result from the cited public record. A reporting limit is the lowest level the method could reliably quantify; a non-detect is not a guarantee of zero.

  • UCMR5 Analytical Results

    UCMR5 Analytical Results: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)

    US EPA

    Published
    2026-01-15
    Newest sample
    2024-07-08
    Findings here
    30

    View source ↗Source record

  • State SDWIS Compliance Record

    Lead & Copper Rule 90th-percentile: LOS OSOS COMMUNITY SERVICES DISTRICT (CA4010016)

    US EPA SDWIS

    Published
    2026-07-09
    Newest sample
    2026
    Findings here
    1

    View source ↗Source record

Methodology: how we analyze water. Prepared with AI assistance and reviewed by the PurityMap Editorial Team before publication.

Data & methodologyHow we analyze waterData integrity policy

Something off with your water's smell, color or taste?

Start with the hot-or-cold tap check. Where Los Osos Community Services District reported something related, it's shown below.

ZIP codes in Los Osos

A ZIP code is a postal area, not a water service area. Your water bill names your supplier.