ATASCADERO MUTUAL WATER COlikely match

City water report · 2026

Is Atascadero Tap Water Safe? 2026 Water Quality Report

Short answer: Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and copper (90th percentile) are above their federal limits; lithium sits above a screening level. Atascadero Mutual Water Co serves 33,307 residents.

Explore the findings What can I do?Follow

Likely match, check your bill

ATASCADERO MUTUAL WATER CO serves Atascadero

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

Source: Groundwater

ATASCADERO MUTUAL WATER COThis report
CA4010002 · 33,307 served

What stands out

Three results above their listed limits

Each bar is drawn in blocks of its own limit, so the length shows how far above it the result sits.

PFOS

Perfluorooctanesulfonic acid

5.6× the limit

22.3ng/L

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

EPA UCMR 5 · sampled 2023Evidence

PFOA

Perfluorooctanoic acid

2.1× the limit

8.4ng/L

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

EPA UCMR 5 · sampled 2023Evidence

Copper

1.2× the limit

1.5mg/L

Each block = 1.3 mg/L federal action level

EPA SDWIS (Lead & Copper Rule) · sampled 2018Evidence

Coverage by group

32 results on record

PFAS (forever chemicals)
2 above · 3 detected · 24 not detected
Metals & lead
1 above · 1 not detected
Disinfection by-productsNot monitored
Other
1 above

Every detected result

7 detected results, by distance from their limit

ATASCADERO MUTUAL WATER CO (EPA PWSID CA4010002) delivers groundwater to 33,307 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.

Perfluorooctanesulfonic acid (PFOS)EPA UCMR 5 · 2023
4.0 ng/L federal MCL (2024)
22.3ng/L
Above limit
Perfluorooctanoic acid (PFOA)EPA UCMR 5 · 2023
4.0 ng/L federal MCL (2024)
8.4ng/L
Above limit
LithiumEPA UCMR 5 · 2023
10 µg/L EPA health reference level (screening, not a legal limit)
20.7µg/L
Above screening
Copper (90th percentile)EPA SDWIS (Lead & Copper Rule) · 2018
1.3 mg/L federal action level
1.5mg/L
Above limit
Perfluorohexanesulfonic acid (PFHxS)EPA UCMR 5 · 2023
10 ng/L federal MCL (2024)
7.6ng/L
Within reference
Perfluorobutanesulfonic acid (PFBS)EPA UCMR 5 · 2023
2,000 ng/L EPA health advisory (screening, not a legal limit)
9.4ng/L
Within reference
Perfluorobutanoic acid (PFBA)EPA UCMR 5 · 2023
No federal or state limit; shown for transparency
10ng/L
Detected · no limit

25 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
PFHpA
PFHpS
PFHxA
PFMBA
PFMPA
PFNA
PFPeA
PFPeS
PFTA
PFTrDA
PFUnA
Lead (90th percentile)

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

01 · TestTest your own tap
A tap test can confirm levels at your home before you choose treatment.
Certified lab
How to test your tap →
02 · Treat PFASReverse osmosis, or carbon certified for PFAS
PFOS 22.3 ng/L, above the 4 ng/L limit (+4 more PFAS detected)
NSF/ANSI 58 or 53, with PFOA/PFOS/PFBS/PFHxS/PFBA named on the listing
Treatment for PFAS →
03 · Treat Copper (90th percentile), LithiumDepends on the contaminant
Copper (90th percentile) 1.5 mg/L, above the 1.3 mg/L federal action level; Lithium 20.7 µg/L, above the 10.0 µg/L EPA health reference level
The certifier's listing for each named contaminant
Treatment for Copper (90th percentile), Lithium →

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
Watersafe Drinking Water Test Kit
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
- Turnaround: Minutes; the bacteria test can take up to 48 hours
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.
Check price on Amazon
Lab-certified results
ETR Labs Basic Water Quality Test Kit
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
- Analyzed by Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638
- Turnaround: 2–4 business days after the lab receives it
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.
Check price on Amazon

When your results arrive, read them here →

Commercial

Certified for a concern found here

Each card names which Atascadero 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
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check 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
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

See all 9 products certified for a Atascadero concern →

Countertop System

Aquasana Clean Water Machine Countertop Filter (AQ-CWM2)

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Countertop System

Patriot Pure Ultimate Water Filtration System

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Countertop System

AquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100)

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Countertop System

AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Under-Sink Filter

Waterdrop G3P600 Tankless Reverse-Osmosis System

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Under-Sink Filter

Waterdrop G3P800 Tankless Reverse-Osmosis System

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Refrigerator Filter

Whirlpool Filter 3 Refrigerator Water Filter (WHR3RXD1)

PFOA: eligible, evidence match
PFOS: eligible, evidence match
Not established: Copper (90th percentile), Lithium, Perfluorobutanesulfonic acid (PFBS) and 2 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 evidence Check price on Amazon

Questions

Frequently asked questions

Is Atascadero tap water safe to drink?

PurityMap does not give a safe/unsafe verdict; it shows what the public records measured. For Atascadero, PFOS 22.3 ng/L and PFOA 8.4 ng/L were measured above the 4 ng/L federal limit in EPA's 2024 testing. ATASCADERO MUTUAL WATER CO (PWSID CA4010002) has a Purity Score of 32/100 (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 Atascadero?

ATASCADERO MUTUAL WATER CO (PWS ID CA4010002) is the public water system on record for Atascadero, California, serving about 33,307 people. Confirm the utility on your water bill before acting on a specific finding.

Where does Atascadero get its drinking water?

Groundwater (primary source of record in EPA SDWIS).

Are PFAS "forever chemicals" in Atascadero's water?

Yes. In EPA's UCMR 5 testing (2023-04-19 to 2023-10-11), PFOS was measured at 22.3 ng/L against a 4 ng/L federal limit and PFOA was measured at 8.4 ng/L against a 4 ng/L federal limit. PFBS (9.4 ng/L, below the 2,000 ng/L EPA health advisory) and PFHxS (7.6 ng/L, below the 10 ng/L federal limit) were also detected. PFBA (10 ng/L) was also detected; it has 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 Atascadero's tap water?

Lead is not in Atascadero'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.

What does the latest Atascadero water report show?

PurityMap's current record for Atascadero holds 32 findings: 4 above a reference, 2 detected within the reference, 1 detected with no limit and 25 not detected. Each finding links to its dated public record; a parameter that was never monitored is shown as pending, not as a pass.

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Sources and dataAll 32 records and their sourcesEPA UCMR 5 · EPA SDWIS (Lead & Copper Rule)

Contaminant	Result	Benchmark	Status	Sampled	Source
Perfluorooctanesulfonic acid (PFOS)	22.3 ng/L	4.0 ng/L federal MCL (2024)	Above a historical reference; current applicability unverified	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorooctanoic acid (PFOA)	8.4 ng/L	4.0 ng/L federal MCL (2024)	Above a historical reference; current applicability unverified	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Lithium	20.7 µg/L	10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit	Above the referenced health-based guidance value	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Copper (90th percentile)	1.5 mg/L	1.3 mg/L federal action level	Above the listed reference	2018–2018 monitoring period	Lead & Copper Rule 90th-percentile: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorohexanesulfonic acid (PFHxS)	7.6 ng/L	10 ng/L federal MCL (2024)	Within a historical reference; current applicability unverified	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorobutanesulfonic acid (PFBS)	9.4 ng/L	2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit	Within the referenced health-based guidance value	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorobutanoic acid (PFBA)	10 ng/L	No federal or state limit; shown for transparency	Detected, no limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

25 other contaminants tested — none detected

Contaminant	Result	Benchmark	Status	Sampled	Source
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)	< 5 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)	< 5 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)	< 5 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)	< 2 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)	< 5 ng/L	10 ng/L federal MCL (2024)	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Lead (90th percentile)	Non-Detect (ND)	15 µg/L federal action level	Not detected above the reporting limit	2026–2026 monitoring period (still open)	Lead & Copper Rule 90th-percentile: ATASCADERO MUTUAL WATER CO (CA4010002)
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)	< 5 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)	< 6 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)	< 20 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoro-3-methoxypropanoic acid (PFMPA)	< 4 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoro-4-methoxybutanoic acid (PFMBA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorodecanoic acid (PFDA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorododecanoic acid (PFDoA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoroheptanesulfonic acid (PFHpS)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoroheptanoic acid (PFHpA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorohexanoic acid (PFHxA)	< 3 ng/L	400,000 ng/L Michigan EGLE state MCL (strictest US state)	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorononanoic acid (PFNA)	< 4 ng/L	10 ng/L federal MCL (2024)	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoropentanesulfonic acid (PFPeS)	< 4 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoropentanoic acid (PFPeA)	< 3 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorotetradecanoic acid (PFTA)	< 8 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluorotridecanoic acid (PFTrDA)	< 7 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)
Perfluoroundecanoic acid (PFUnA)	< 2 ng/L	No federal or state limit; shown for transparency	Not detected above the reporting limit	2023-04-19 to 2023-10-11	UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorooctanesulfonic acid (PFOS)

Result: 22.3 ng/L
Benchmark: 4.0 ng/L federal MCL (2024)
Status: Above a historical reference; current applicability unverified
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorooctanoic acid (PFOA)

Result: 8.4 ng/L
Benchmark: 4.0 ng/L federal MCL (2024)
Status: Above a historical reference; current applicability unverified
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Lithium

Result: 20.7 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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Copper (90th percentile)

Result: 1.5 mg/L
Benchmark: 1.3 mg/L federal action level
Status: Above the listed reference
Sampled: 2018–2018 monitoring period
Source: Lead & Copper Rule 90th-percentile: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorohexanesulfonic acid (PFHxS)

Result: 7.6 ng/L
Benchmark: 10 ng/L federal MCL (2024)
Status: Within a historical reference; current applicability unverified
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorobutanesulfonic acid (PFBS)

Result: 9.4 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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorobutanoic acid (PFBA)

Result: 10 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Detected, no limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

25 other contaminants 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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Lead (90th percentile)

Result: Non-Detect (ND)
Benchmark: 15 µg/L federal action level
Status: Not detected above the reporting limit
Sampled: 2026–2026 monitoring period (still open)
Source: Lead & Copper Rule 90th-percentile: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorodecanoic acid (PFDA)

Result: < 3 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorododecanoic acid (PFDoA)

Result: < 3 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluoroheptanesulfonic acid (PFHpS)

Result: < 3 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluoroheptanoic acid (PFHpA)

Result: < 3 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorohexanoic acid (PFHxA)

Result: < 3 ng/L
Benchmark: 400,000 ng/L Michigan EGLE state MCL (strictest US state)
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorononanoic acid (PFNA)

Result: < 4 ng/L
Benchmark: 10 ng/L federal MCL (2024)
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluoropentanesulfonic acid (PFPeS)

Result: < 4 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluoropentanoic acid (PFPeA)

Result: < 3 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorotetradecanoic acid (PFTA)

Result: < 8 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluorotridecanoic acid (PFTrDA)

Result: < 7 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

Perfluoroundecanoic acid (PFUnA)

Result: < 2 ng/L
Benchmark: No federal or state limit; shown for transparency
Status: Not detected above the reporting limit
Sampled: 2023-04-19 to 2023-10-11
Source: UCMR5 Analytical Results: ATASCADERO MUTUAL WATER CO (CA4010002)

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: ATASCADERO MUTUAL WATER CO (CA4010002)
US EPA
Published
2026-01-15
Newest sample
2023-10-11
Findings here
30
View source ↗Source record
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: ATASCADERO MUTUAL WATER CO (CA4010002)
US EPA SDWIS
Published
2026-07-09
Newest sample
2026
Findings here
2
View source ↗Source record

Methodology: how we analyze water.

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 Atascadero Mutual Water Co reported something related, it's shown below.

Rotten-egg smell
Cloudy or milky water
Chlorine smell
Brown or yellow water
Metallic taste
Lead at Atascadero Mutual Water Co: not detected (90th percentile, 2026 monitoring period (still open)). Lead has no taste, so a taste neither shows nor rules it out.
Copper: 1.5 mg/L (90th percentile, 2018 monitoring period). The federal action level is 1.3 mg/L.

ZIP codes in Atascadero

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

ATASCADERO MUTUAL WATER CO serves Atascadero

Three results above their listed limits

Perfluorooctanesulfonic acid

Perfluorooctanoic acid

Copper

Coverage by group

7 detected results, by distance from their limit

Test first, then treat what was found

Test your own tap

Watersafe Drinking Water Test Kit

ETR Labs Basic Water Quality Test Kit

Certified for a concern found here

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

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

Aquasana Clean Water Machine Countertop Filter (AQ-CWM2)

Patriot Pure Ultimate Water Filtration System

AquaTru Carafe Countertop Reverse-Osmosis Purifier (AT100)

AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)

Waterdrop G3P600 Tankless Reverse-Osmosis System

Waterdrop G3P800 Tankless Reverse-Osmosis System

Whirlpool Filter 3 Refrigerator Water Filter (WHR3RXD1)

Frequently asked questions

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

ZIP codes in Atascadero