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  1. PurityMap
  2. Water Quality
  3. California
  4. NORWALK - CITY, WATER DEPT.CA1910191
Change
Updated 2026-09-16
Water system record · CA1910191

Norwalk - City, Water Dept.

Norwalk - City, Water Dept. serves 20,283 people from surface water. 31 results are on record. 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.

Explore the findingsIs this my supplier?Follow
Purity ScoreHow the 57 is builtCA1910191 · 20,283 served
57/100 · FairConfidence: moderate
above a reference
3
detected, within reference or no limit
3
not detected
25
  • PFAS (forever chemicals)0
  • Metals & lead100
  • Disinfection by-products—Not monitored
  • Track record (violations)100

Subject scores out of 100. 3 of 4 subjects measured; disinfection pending a source.

Not in this score: Lithium. Listed in the findings, not graded by the Purity Score.

System-level record, not a test of your tap. How we score

Source
Surface Water
Serves 1 city area on record.
Population
20,283
as reported to EPA
Type
Community Water System
California
Cities
1
Norwalk
Records
31 results
latest 2024
FindingsAll resultsComplianceWhat you can doProductsRecordsFAQ
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.

PFOS

Perfluorooctanesulfonic acid

6.5× the limit

26ng/L

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

EPA UCMR 5 · sampled 2024Evidence
PFOA

Perfluorooctanoic acid

1.3× the limit

5.2ng/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 · 3 detected · 24 not detected
  • Metals & lead
    1 not detected
  • Disinfection by-products
    Not monitored
  • Other
    1 above
  • Above a limit or reference
  • Detected
  • Not detected
  • Not monitored
Every detected result

6 detected results, by distance from their limit

  • PFOS
    Perfluorooctanesulfonic acid (PFOS)EPA UCMR 5 · 2024
    4.0 ng/L federal MCL (2024)
    26ng/L
    Above limit
  • Li
    LithiumEPA UCMR 5 · 2024
    10 µg/L EPA health reference level (screening, not a legal limit)
    59µg/L
    Above screening
  • PFOA
    Perfluorooctanoic acid (PFOA)EPA UCMR 5 · 2024
    4.0 ng/L federal MCL (2024)
    5.2ng/L
    Above limit
  • PFHxS
    Perfluorohexanesulfonic acid (PFHxS)EPA UCMR 5 · 2024
    10 ng/L federal MCL (2024)
    7.6ng/L
    Within reference
  • PFBA
    Perfluorobutanoic acid (PFBA)EPA UCMR 5 · 2024
    No federal or state limit; shown for transparency
    5.6ng/L
    Detected · no limit
  • PFPeA
    Perfluoropentanoic acid (PFPeA)EPA UCMR 5 · 2024
    No federal or state limit; shown for transparency
    3.4ng/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
  • PFBS
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpA
  • PFHpS
  • PFHxA
  • PFMBA
  • PFMPA
  • PFNA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA
  • Lead (90th percentile)

Compliance and coverage

Lead service lines

5,675service lines inventoried

  • Lead0
  • Galvanized, to replace551
  • Material unknown33
  • Not lead5,091

From the utility's inventory reported to EPA (2026Q2). Look up your address with the utility.

Compliance

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.

A federal limit (an MCL or action level) is an enforceable legal cap; a health goal is often stricter. Meeting the limit is a compliance fact, not a health clearance, and PurityMap publishes no overall compliance verdict.

What you can do

Test first, then treat what was found

  1. 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 →
  2. 02 · Treat PFASReverse osmosis, or carbon certified for PFAS

    PFOS 26 ng/L, above the 4 ng/L limit (+4 more PFAS detected)

    NSF/ANSI 58 or 53, with PFOA/PFOS/PFHxS/PFBA/PFPeA named on the listing
    Treatment for PFAS →
  3. 03 · LithiumDepends on the contaminant

    Lithium 59 µg/L, above the 10.0 µg/L EPA health reference level

    The certifier's listing for each named contaminant
    Treatment for Lithium →

Understand water treatment technologies →

Understand:PFAS in Norwalk

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
Commercial

Certified for a concern found here

Each card names which of this system’s 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 3-Stage Max Flow Under-Sink Filter (AQ-6300M)

  • ✓PFOA: eligible, evidence match
  • ✓PFOS: eligible, evidence match
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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
Countertop System

Aquasana Clean Water Machine Countertop Filter (AQ-CWM2)

  • ✓PFOA: eligible, evidence match
  • ✓PFOS: eligible, evidence match
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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
See all 6 products certified for a concern in this system →
Countertop System

AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)

  • ✓PFOA: eligible, evidence match
  • ✓PFOS: eligible, evidence match
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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

Under-Sink Reverse-Osmosis System

  • ✓PFOA: eligible, evidence match
  • ✓PFOS: eligible, evidence match
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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 G3P600 Tankless Reverse-Osmosis System

  • ✓PFOA: eligible, evidence match
  • ✓PFOS: eligible, evidence match
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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
  • –Not established: Lithium, PFHxS, Perfluorobutanoic acid (PFBA) and 1 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
Questions

Frequently asked questions

Who does NORWALK - CITY, WATER DEPT. serve?

NORWALK - CITY, WATER DEPT. (PWS ID CA1910191) is a public water system serving 20,283 people in Norwalk, California.

Where does NORWALK - CITY, WATER DEPT. get its water?

NORWALK - CITY, WATER DEPT. is on record as drawing from surface water. The source shapes which contaminants matter most for this system.

What does NORWALK - CITY, WATER DEPT.'s monitoring record show?

PurityMap's record for NORWALK - CITY, WATER DEPT. holds 31 findings: 3 above a reference, 1 detected within the reference, 2 detected with no limit and 25 not detected, from 31 evidence records. Every finding links to its source; a substance that was never monitored is shown as pending, not as a pass.

Is NORWALK - CITY, WATER DEPT.'s water safe to drink?

PurityMap does not issue a safety verdict. It publishes NORWALK - CITY, WATER DEPT.'s measured results against each contaminant's benchmark so you can read them in context. Safety depends on the specific finding, your plumbing, and how the water reaches your tap.

How current is this NORWALK - CITY, WATER DEPT. data?

The latest published record for NORWALK - CITY, WATER DEPT. is dated 2026-09-16. Utilities report on regulatory cycles, so results reflect the monitoring period rather than a live reading.

Does this assessment represent my home's tap water?

No. It is assessed at the water-system level from NORWALK - CITY, WATER DEPT.'s own monitoring. It does not cover the service line to your building or the plumbing inside it, which can add lead and other metals after the water leaves the system. A tap test is the way to know what reaches your glass.

What contaminants were detected in NORWALK - CITY, WATER DEPT.?

Perfluorooctanesulfonic acid (PFOS), Lithium, Perfluorooctanoic acid (PFOA), Perfluorohexanesulfonic acid (PFHxS), Perfluorobutanoic acid (PFBA) and Perfluoropentanoic acid (PFPeA) were detected in this record. Each finding shows its measured value, its reference and its source on this page.

What should I do if I'm concerned about PFAS in NORWALK - CITY, WATER DEPT.'s water?

Start with what the record shows: the PFAS findings above list each measured value against its reference. This record cannot show your home's plumbing, so a tap test tells you what reaches your glass. If you decide to treat your water, look for a filter whose certification covers the specific PFAS compounds in your record; the section "Certified for a concern found here" lists only products with a current certification record for these concerns.

Follow this water

Follow Norwalk - City, Water Dept.

One email when a new sampling round is published, a result moves above or below its reference, or the system's score changes.

Double opt-in: we email a confirmation link. Unsubscribe anytime. No spam.

Cities served by this system
  • Norwalk

As listed for this system in EPA's records. Your water bill names your supplier.

Sources and dataAll 31 records and their sourcesEPA UCMR 5 · EPA SDWIS (Lead & Copper Rule)+
SubstanceResultReferenceSampledStatusEvidence
11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)< 5 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)< 5 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)< 5 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)< 2 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)< 5 ng/L10 ng/L federal MCL (2024)2024-02-27 to 2024-11-20Not detected—
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)< 5 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)< 20 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)< 6 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorobutanoic acid (PFBA)5.6 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Detected, no limitView evidence
Perfluorobutanesulfonic acid (PFBS)< 3 ng/L2,000 ng/L EPA health advisory (screening, not a legal limit)2024-02-27 to 2024-11-20Not detected—
Perfluorodecanoic acid (PFDA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorododecanoic acid (PFDoA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluoroheptanoic acid (PFHpA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluoroheptanesulfonic acid (PFHpS)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorohexanoic acid (PFHxA)< 3 ng/L400,000 ng/L Michigan EGLE state MCL (strictest US state)2024-02-27 to 2024-11-20Not detected—
Perfluorohexanesulfonic acid (PFHxS)7.6 ng/L10 ng/L federal MCL (2024)2024-02-27 to 2024-11-20Below limitView evidence
Perfluoro-4-methoxybutanoic acid (PFMBA)< 3 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluoro-3-methoxypropanoic acid (PFMPA)< 4 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorononanoic acid (PFNA)< 4 ng/L10 ng/L federal MCL (2024)2024-02-27 to 2024-11-20Not detected—
Perfluorooctanoic acid (PFOA)5.2 ng/L4.0 ng/L federal MCL (2024)2024-02-27 to 2024-11-20Above guidelineView evidence
Perfluorooctanesulfonic acid (PFOS)26 ng/L4.0 ng/L federal MCL (2024)2024-02-27 to 2024-11-20Above guidelineView evidence
Perfluoropentanoic acid (PFPeA)3.4 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Detected, no limitView evidence
Perfluoropentanesulfonic acid (PFPeS)< 4 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorotetradecanoic acid (PFTA)< 8 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluorotridecanoic acid (PFTrDA)< 7 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Perfluoroundecanoic acid (PFUnA)< 2 ng/LNo federal or state limit; shown for transparency2024-02-27 to 2024-11-20Not detected—
Lithium59 µg/L10 µg/L EPA health reference level (screening, not a legal limit)2024-02-27 to 2024-11-20Above guidelineView evidence
Lead (90th percentile)Non-Detect (ND)15 µg/L federal action level2020–2022 monitoring periodNot detectedView evidence
  • UCMR5 Analytical Results

    UCMR5 Analytical Results: NORWALK - CITY, WATER DEPT. (CA1910191)

    US EPA

    Published
    2026-01-15
    Newest sample
    2024-11-20
    Findings here
    30

    View source ↗Source record

  • State SDWIS Compliance Record

    Lead & Copper Rule 90th-percentile: NORWALK - CITY, WATER DEPT. (CA1910191)

    US EPA SDWIS

    Published
    2026-07-09
    Newest sample
    2022
    Findings here
    1

    View source ↗Source record

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