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MD 43 Miami Creek Knolls

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
100 people
Connections
26
Water source
Groundwater
Based in
Madera, CA
County
Madera
Owner
Local government
Hardness
Moderately hard
The ZIP code it serves

93644

The short answer

3 results are above the health goal. The worst: Nitrate, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Nitrate, arsenic, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5): California’s own results, samples taken from Sept. 28, 2020 to March 16, 2026, with EPA’s 2012 to 2019 file for earlier years.

Uranium: EPA’s compliance monitoring file, samples taken from Feb. 19, 2014 to March 18, 2016. Newer results are in the utility’s annual water quality report.

Above the health goal3

Nitrate

Comes from the source

Above the health goal

17ppm

Highest sample; found in 1 of 11

2026: not found

One sample, in 2023, was above EPA’s legal limit of 10 ppm, at 17 ppm. No follow-up sample at that point within 30 days is on file. 10 ppm is also EPA’s health goal. In 2026, the latest year on file, it wasn’t found in its one sample. EPA recorded no violation for nitrate at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 9.0 ppm, in 2014.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Arsenic

Comes from the source

Above the health goal

7.4ppb

Highest yearly average, 2022 to 2025

2025, one sample: 7.0 ppb

Averaged by year, the highest was 7.4 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2025, the latest year on file, its one sample was 7.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.1 ppb, in 2019.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Uranium

Comes from the source

Above the health goal

1.9ppb

Highest yearly average, 2014 to 2016

2016, one sample: 1.6 ppb

Averaged by year, the highest was 1.9 ppb, in 2014: below EPA’s legal limit of 30 ppb, but above its health goal of zero. In 2016, the latest year on file, its one sample was 1.6 ppb.

What handles it

Below EPA’s limits2

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.24ppm

Highest yearly average, 2022 to 2025

2025, one sample: 0.21 ppm

Averaged by year, the highest was 0.24 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its one sample was 0.21 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.24 ppm, in 2016.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

1.2ppb

Highest yearly average, 2022 to 2025

2025: not found

Averaged by year, the highest was 1.2 ppb, in 2023, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.9 ppb, in 2018.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Haloacetic acids (HAA5)
  • Lead

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: Nitrate/Nitrite (30 ppm challenge), Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Arsenic

    Other certifiers’ wording: Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Uranium

    For: Nitrate, Arsenic, Uranium

    Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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 reverse osmosis systems, ranked

Hardness

Moderately hard, 77 mg/L (4.5 grains per gallon), at its one sampling point, 2019 to 2025.

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 4.5 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Nitrate, arsenic, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Uranium comes from EPA’s file alone, which ends in 2019. MD 43 Miami Creek Knolls’s own annual report, which it must send you every year, has newer results for those and 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 Sept. 28, 2020 to March 16, 2026; EPA’s compliance samples are from Feb. 19, 2014 to March 18, 2016.

Testing your own tap

MD 43 Miami Creek Knolls’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 MD 43 Miami Creek Knolls serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • SGS North America, Inc.

    Clovis, CA · about 37 miles

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

    (559) 862-2118

  • BSK Associates

    Fresno, CA · about 44 miles

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

    (559) 497-2888

  • Dellavalle Laboratory, Inc.

    Fresno, CA · about 44 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, radioactivity

    (559) 233-6129

All 145 certified labs for California

Sources

PWSID CA2000557. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Madera County

All California utilities

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