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Knights Ferry Comm. Svc. Dist.

What EPA’s and California’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
168 people
Connections
67
Water source
Surface water
Based in
Knights Ferry, CA
County
Stanislaus
Owner
Local government
Hardness
Soft
The ZIP code it serves

95361

The short answer

1 result is above EPA’s legal limit, 1 more is above the limit’s level with no violation recorded, and 1 more is above the health goal. The worst: Copper, above the action level. 6 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2021. Lead at 0.34 mg/L (2024) is left out of this report: more than 20 times the action level, it looks like µg/L entered as mg/L.

Total trihalomethanes (TTHM), haloacetic acids (HAA5), arsenic, chromium (total), fluoride and nitrate: California’s own results, samples taken from Feb. 12, 2020 to May 6, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Copper

Comes from pipes, often your own

Above the action level

1.4ppm

90th percentile, 2021

In the latest period, 9 in 10 homes sampled were at or below 1.4 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Above the limit’s level, no violation recorded1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the limit’s level, no violation

146ppb

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 146 ppb, in 2026, above EPA’s legal limit of 80 ppb. That was also the latest year on file. EPA judges this limit on running averages at each sampling point, and recorded no violation for total trihalomethanes (TTHM) at this utility since 2020. Results like these with no violation often include water sampled before treatment or blending; the utility’s annual report says what reaches the tap.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

2.9ppb

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 2.9 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Below EPA’s limits1

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

48.9ppb

Highest yearly average, 2020 to 2026

2026, one sample: 7.4 ppb

Averaged by year, the highest was 48.9 ppb, in 2024, below EPA’s legal limit of 60 ppb. Its highest single sample was 68.6 ppb. In 2026, the latest year on file, its one sample was 7.4 ppb. EPA recorded no violation for haloacetic acids (HAA5) at this utility since 2020.

What handles it

No certification claim covers this compound yet.

4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Fluoride
  • Nitrate

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: Copper Reduction, Trihalomethanes (TTHM) Reduction, Lead Reduction

    For: Copper, Total trihalomethanes (TTHM), Lead

    Other certifiers’ wording: VOC Reduction

  • NSF/ANSI 58

    Claims: Copper Reduction, Trihalomethanes (TTHM) Reduction, Lead Reduction

    For: Copper, Total trihalomethanes (TTHM), Lead

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best water filters for lead, ranked

Hardness

Soft, 27 mg/L (1.6 grains per gallon), at its one sampling point, 2019 to 2026.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 1.6 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2017 to Dec. 31, 20170.095 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2017 to Sept. 30, 20170.099 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 20170.1 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2017 to March 31, 20170.1 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2016 to Dec. 31, 20160.099 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2016 to March 31, 20160.092 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), haloacetic acids (HAA5), arsenic, chromium (total), fluoride and nitrate results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Knights Ferry Comm. Svc. Dist.’s own annual report, which it must send you every year, has the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; California’s results run from Feb. 12, 2020 to May 6, 2026.

Testing your own tap

Knights Ferry Comm. Svc. Dist.’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab California certifies.

The 3 labs California certifies closest to the area Knights Ferry Comm. Svc. Dist. serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Aemtek, Inc.

    Modesto, CA · about 14 miles

    Certified for bacteria

    (510) 979-1979

  • Institute of Environmental Health, Inc. dba IEH-JL Analytical

    Modesto, CA · about 18 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (209) 538-8111

  • Microbac Laboratories, Inc. - Turlock

    Turlock, CA · about 21 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity

    (707) 822-4649

All 145 certified labs for California

Sources

PWSID CA5000008. Rebuilt from EPA data on Oct. 18, 2026.

Also in Stanislaus County

All California utilities

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