Tap water and drinking water quality in Fremont, CA

WATER QUALITY REPORT

Fremont, CA tap water: what’s in it in 2026

Q: Is Fremont tap water safe to drink in 2026?

Fremont earns Water Safety Grade A- (80/88) on WaterCheckup - PFAS Concern. Known issues include pfas from industrial sites. Certified filtration is strongly recommended.

Q: Does Fremont water have PFAS?

EPA UCMR5 monitoring for Fremont (PWSID CA3700963) is on this page. Check the table below for the latest UCMR5 snapshot. Only reverse osmosis (NSF 58) or NSF P473-certified filters reliably remove PFAS; standard pitchers do not.

Q: Does Fremont water have lead?

Lead usually comes from service lines and building plumbing in Fremont, not the treatment plant. Pre-1986 homes are highest risk. NSF 53-certified pitchers or reverse osmosis remove lead at the tap.

Q: What water filter is best for Fremont?

For Fremont's profile (PFAS Concern), reverse osmosis covers PFAS, lead, and disinfection byproducts. Renters can use a countertop RO; homeowners often choose under-sink NSF 58 systems ranked on this page.

Reviewed by Joe Letorney, 30-year water treatment expert · Former WQA Certified Water Treatment Specialist (CWS), Level VI

See best water filters for lead removal and what filters remove PFAS.

Serving 230K residents via Alameda County Water District · Fremont, CA drinking water is supplied by Alameda County Water District. EPA and public water system monitoring commonly focus on issues such as PFAS from industrial sites, Chromium-6, Nitrates. Drought rules, inter-tie agreements, and emergency blending can temporarily move where your water is sourced from—even when the public water system name stays the same. Enter your ZIP to see how current source routing and treatment performance show up in federal databases for your system this year.

Check water hardness in Fremont →

PFAS from industrial sitesChromium-6Nitrates

80/ 88

WATERCHECKUP SAFETY SCORE

Grade: A-

Good

WaterCheckup Safety Score — an independent index from EPA public data and our formula. Not your utility’s official water quality rating, an EPA compliance grade, or a test of water at your tap. How we score →

Same score for your ZIP — look up your ZIP for the full contaminant report

✅

GENERALLY OK

Based on water safety score

WHAT YOU SHOULD KNOW ABOUT FREMONT WATER

Fremont water currently shows no major violations in EPA monitoring data. That said, your home's internal plumbing can add lead or other contaminants after water leaves the treatment plant — especially in homes built before 1986.

⚠PFAS from industrial sites

⚠Chromium-6

⚠Nitrates

Public water systems in California

18,760

EPA PWSID (this report)

CA0110001

TTHMs (utility avg.)

41.3 ppb

HAA5 (utility avg.)

27.3 ppb

Browse California utilities →

LEGAL DOES NOT ALWAYS MEAN SAFE

Fremontwater may meet federal EPA limits while still showing contaminants above independent health guidelines (EWG, state advisories). EPA MCLs are often set on treatment feasibility — not a "zero risk" threshold. Compare levels below to health guidelines and state/U.S. utility averages, then see which filter technologies address your profile.

CONTAMINANTS IN FREMONT WATER

EPA UCMR5 PFAS plus utility/EWG averages from our contaminant bundle. Run a ZIP report for live SDWIS samples at your address.

Total Trihalomethanes (TTHMs)

41.3 ppb (EPA limit 80 ppb)275.3× health guidelineModerate

This utility

41.3

U.S. avg

31.0

State avg

26.5

EWG health guideline: 0.15 ppb

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 30.97 ppb · CA utility avg: 26.50 ppb

Removes with: RO · Carbon

Perfluorooctane sulfonate (PFOS)

2.55 ppt (EPA limit 4 ppt)Moderate

This utility

2.55

U.S. avg

3.32

State avg

3.91

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 3.32 ppt · CA utility avg: 3.91 ppt

Removes with: RO

Chlorate

222.9 ppbLower concern

This utility

223

U.S. avg

161

State avg

121

Can impair thyroid function — most concerning during pregnancy and childhood.

Removes with: RO · Carbon

Haloacetic Acids (HAA5)

27.3 ppb (EPA limit 60 ppb)455× health guidelineLower concern

This utility

27.3

U.S. avg

21.6

State avg

35.0

EWG health guideline: 0.06 ppb (HAA5)

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 21.57 ppb · CA utility avg: 35.03 ppb

Removes with: RO · Carbon

Haloacetic Acids (HAA9)

12.6 ppbLower concern

This utility

12.6

U.S. avg

23.6

State avg

15.6

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 23.64 ppb · CA utility avg: 15.58 ppb

Removes with: RO · Carbon

Perfluorohexane sulfonate (PFHXS)

1.38 ppt (EPA limit 10 ppt)Lower concern

This utility

1.38

U.S. avg

2.25

State avg

1.89

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 2.25 ppt · CA utility avg: 1.89 ppt

Removes with: RO

Manganese

1.23 ppbLower concern

This utility

1.23

U.S. avg

5.69

State avg

3.99

EWG health guideline: 100 ppb

Long-term exposure at high levels may affect the nervous system. Staining and taste issues at lower levels.

Removes with: RO · Carbon

Bromate

1.18 ppb (EPA limit 10 ppb)Lower concern

This utility

1.18

U.S. avg

1.64

State avg

2.20

Probable human carcinogen. Kidney toxicity at high exposure.

Removes with: RO · Carbon

Perfluorobutane sulfonate (PFBS)

1.06 pptLower concern

This utility

1.06

U.S. avg

1.89

State avg

1.34

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 1.89 ppt · CA utility avg: 1.34 ppt

Removes with: RO

Perfluorobutanoic Acid (PFBA)

1.04 pptLower concern

This utility

1.04

U.S. avg

3.38

State avg

1.51

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 3.38 ppt · CA utility avg: 1.51 ppt

Removes with: RO

Fluoride

0.752 ppm (EPA limit 4 ppm)Lower concern

This utility

0.75

U.S. avg

0.49

State avg

0.35

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 0.49 ppm · CA utility avg: 0.35 ppm

Removes with: RO · Ion exchange

Vanadium

0.43 ppbLower concern

This utility

0.43

U.S. avg

2.40

State avg

6.22

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 2.40 ppb · CA utility avg: 6.22 ppb

Removes with: RO · Carbon

Molybdenum

0.4 ppbLower concern

This utility

0.40

U.S. avg

2.35

State avg

3.41

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 2.35 ppb · CA utility avg: 3.41 ppb

Removes with: RO · Carbon

Nitrate and nitrite

0.332 ppm (EPA limit 10 ppm)Lower concern

This utility

0.33

U.S. avg

1.04

State avg

1.77

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 1.04 ppm · CA utility avg: 1.77 ppm

Removes with: RO · Carbon

Nitrate

0.328 ppm (EPA limit 10 ppm)2.3× health guidelineLower concern

This utility

0.33

U.S. avg

1.10

State avg

2.40

EWG health guideline: 0.14 ppm

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 1.10 ppm · CA utility avg: 2.40 ppm

Removes with: RO

Strontium

0.2 ppbLower concern

This utility

0.20

U.S. avg

0.60

State avg

1.11

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 0.60 ppb · CA utility avg: 1.11 ppb

Removes with: RO · Carbon

Chromium-6

0.14 ppb7× health guidelineLower concern

This utility

0.14

U.S. avg

0.54

State avg

1.32

EWG health guideline: 0.02 ppb (chromium-6)

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 0.54 ppb · CA utility avg: 1.32 ppb

Removes with: RO

Perfluorohexanoic Acid (PFHxA)

0.06 pptLower concern

This utility

0.06

U.S. avg

2.85

State avg

1.93

EWG Tap Water Atlas utility average (2021–2023) · U.S. utility avg (EWG Atlas sample): 2.85 ppt · CA utility avg: 1.93 ppt

Removes with: RO

U.S. and state averages from EWG Tap Water Atlas utilities in our database. For your exact tap, use a ZIP report — home plumbing can differ from utility averages.

Fremont's East Bay location puts it in a zone with documented PFAS contamination from industrial operations.

Chromium-6 has been detected in East Bay water above California health goals.

Agricultural nitrates from the Livermore and Sunol valleys affect some Alameda County water sources.

RO handles PFAS, chromium-6, and nitrates -- the full Fremont contamination profile.

PFAS TESTING — EPA UCMR5 DATA

EPA UCMR5 monitoring · Testing period 2023–2025 · Last updated Q1 2026

📋

No UCMR5 data on file for this system

The EPA's 5th Unregulated Contaminant Monitoring Rule (UCMR5) required systems serving 3,300+ people to test for 29 PFAS compounds between 2023–2025. This system either was not required to test, reported no detections, or has not yet submitted results to the federal database.

Source: EPA UCMR5 national dataset · Data current as of 2026

🔔 Get alerts if Fremont's water data changes:

WHICH FILTER TECHNOLOGY WORKS FOR FREMONT?

Reference matrix — not specific brands. NSF-certified carbon blocks, reverse osmosis (NSF 58), and ion-exchange softeners address different contaminants. Product picks below match this profile.

Contaminant

Carbon

Ion exch.

Total Trihalomethanes (TTHMs)

✓

—

Perfluorooctane sulfonate (PFOS)

—

✓

—

Haloacetic Acids (HAA5)

✓

—

Nitrate

—

✓

—

Chromium-6

—

✓

—

TEST YOUR TAP OR FILTER NOW?

Fremontutility data is a strong baseline — but lead often comes from your home's pipes, and PFAS can vary by neighborhood. Choose certified lab testing for certainty, or skip straight to NSF-certified filters matched to this profile.

STEP 1 · VERIFY AT YOUR FAUCET

Test before you buy a $300+ filter

SimpleLab Tap Score mail-in panels test PFAS, lead, nitrates, bacteria, and 100+ contaminants at your kitchen tap. Results in about a week — then pick filtration with real numbers, not guesses.

Tap Score City Test — from $89 →

Accredited labs · Best if you have old plumbing, pregnancy, or want proof before installing RO

STEP 2 · FIX IT NOW

Ready to filter based on this report?

Get NSF 58 / NSF 53 picks matched to Fremont's PFAS, lead, and disinfection byproduct profile — reviewed by a 30-year water treatment expert.

Take the 3-question filter quiz →

Best when contaminants are already flagged above and you want the right RO or pitcher today

Clean water splash — certified water filter recommendations

WHAT TO DO ABOUT IT

Based on Fremont's water profile above, here's the exact system we recommend — and why it's right for this water supply specifically.

TOP PICKS FOR FREMONT

⚠ Contaminants detected in local water

Aquasana SmartFlow RO

MOST CERTIFIED

Aquasana · ~$449

WQA Gold Seal + NSF 42/53/58/401. Most certifications of any under-sink RO. Removes 90+ contaminants.

WHY THIS FOR FREMONT · Chosen for Fremont because PFAS contamination is detected in this system's UCMR5 data — reverse osmosis is the most effective residential technology, removing 99%+ of PFAS compounds.

Amazon →

AquaTru Under-Sink RO

EASIEST FILTER CHANGE

AquaTru · ~$375

NSF 42/53/58 certified. Quick-change filters, no tools. Compact tankless design, 4-stage filtration.

Amazon →

Not sure which filter is right for you? Take the 3-question quiz →

WATER SYSTEM -- EPA SDWIS

System Name

Alameda County Water District

EPA PWSID

CA0110001

Population Served

230K

State

COMMON QUESTIONS

Is Fremont tap water safe to drink in 2026?

Fremont water meets EPA legal standards, but meeting legal standards is not the same as being free of health concerns. EPA limits are set based on treatment feasibility, not always on what independent scientists consider safe. Fremont has pfas from industrial sites which is a significant concern — certified filtration is strongly recommended.

Does Fremont water have PFAS?

EPA UCMR5 monitoring data for Fremont (water system CA3700963) is shown above. PFAS — sometimes called "forever chemicals" — are synthetic compounds that don't break down in the body. Only reverse osmosis systems or NSF 58-certified carbon block filters reliably remove PFAS from tap water. Standard pitcher filters do not remove PFAS.

Does Fremont water have lead?

Lead in tap water almost always comes from the pipes inside your home or building, not the treatment plant. Homes built before 1986 in Fremont are most at risk because they may have lead solder, brass fittings, or lead service lines. The EPA has no safe level for lead in children. An NSF/ANSI 53-certified filter or reverse osmosis system removes lead at the tap.

What water filter is best for Fremont?

For Fremont's water profile — pfas from industrial sites, chromium-6 — a reverse osmosis system addresses the widest range of contaminants. Under-sink RO (Waterdrop G3P600, Aquasana SmartFlow) is the gold standard for homeowners. Renters can use a countertop RO like the Waterdrop K19-S Countertop RO — zero installation required. Clearly Filtered pitchers are the best non-RO option for PFAS and lead.

How do I get my Fremont water tested?

For the most accurate results for your specific tap, use a certified mail-in lab test rather than relying on city-wide data. SimpleLab Tap Score tests for 100+ contaminants including PFAS, lead, arsenic, and nitrates. Results come with a detailed health assessment and filter recommendations. City-wide EPA data like what you see above is a strong baseline, but your home's plumbing can add contaminants after the water leaves the treatment plant.

LEAD SERVICE LINE RISK

Does your street have lead pipes?

As of October 2024, all US public water systems must publish a public inventory of their lead service lines — the pipes connecting the water main to your home. Even if your public water system water tests clean at the treatment plant, lead can leach from these pipes into your tap. Homes built before 1986 are most at risk.

EPA Official Service Line Inventory →

Federal LCRR inventory data for Alameda County Water District · PWSID CA3700963

💡 Homes built before 1986 may have lead solder or service lines. A filter certified NSF/ANSI 53 removes lead at the tap regardless of pipe material.

STAY INFORMED

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City-wide data is just the start. Enter your ZIP to see your exact water system's EPA report, PFAS levels, and violation history — then get the right filter for your home.

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