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City of San Juan Bautista

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
2,335 people
Connections
834
Water source
Groundwater
Based in
San Juan Bautista, CA
County
San Benito
Owner
Local government
Hardness
Very hard
The ZIP code it serves

95045

The short answer

3 results are above the health goal. The worst: Nitrate, above the health goal. 4 health-based violations since 2016.

What handles it

What was found

Nitrate, uranium, arsenic, total trihalomethanes (TTHM), fluoride, chromium (total) and haloacetic acids (HAA5): California’s own results, samples taken from Jan. 26, 2020 to March 23, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal3

Nitrate

Comes from the source

Above the health goal

11.2ppm

Highest sample; found in 18 of 27

2026, one sample: 0.7 ppm

In 2020, two samples were above EPA’s legal limit of 10 ppm, the highest 11.2 ppm. Every one came back under the limit on the next sample at the same point. 10 ppm is also EPA’s health goal. In 2026, the latest year on file, its one sample was 0.7 ppm. EPA recorded no violation for nitrate at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 29.3 ppm, in 2018, and EPA recorded violations in 2014 and 2017.

What handles it

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

Uranium

Comes from the source

Above the health goal

4.8ppb

Highest yearly average, 2025

Averaged by year, the highest was 4.8 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 7.3 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.9 ppb, in 2019.

What handles it

Arsenic

Comes from the source

Above the health goal

1.4ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 1.4 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 2.9 ppb. In 2026, 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 0.48 ppb, in 2017.

What handles it

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

Below EPA’s limits4

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

24.5ppb

Highest yearly average, 2020 to 2025

2025 average: 9.0 ppb

Averaged by year, the highest was 24.5 ppb, in 2024, below EPA’s legal limit of 80 ppb. Its highest single sample was 25 ppb. In 2025, the latest year on file, its two samples averaged 9.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 11.2 ppb, in 2016.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.98ppm

Highest yearly average, 2020 to 2026

2026, one sample: 0.5 ppm

Averaged by year, the highest was 0.98 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 1.5 ppm. In 2026, the latest year on file, its one sample was 0.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.67 ppm, in 2017.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

6.8ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 6.8 ppb, in 2020, below EPA’s legal limit of 100 ppb. Its highest single sample was 12 ppb. In 2026, the latest year on file, it wasn’t found in its one sample.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

3.0ppb

Highest yearly average, 2020 to 2025

2025: not found

Averaged by year, the highest was 3.0 ppb, in 2021, below EPA’s legal limit of 60 ppb. Its highest single sample was 6.0 ppb. In 2025, the latest year on file, it wasn’t found in any of its two samples. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 5.5 ppb, in 2016.

What handles it

No certification claim covers this compound yet.

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • 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, Uranium, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Uranium, Arsenic

    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

Very hard, typically 382 mg/L (22.3 grains per gallon), across 2 sampling points, 2020 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 22.3 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Lead and Copper Rule RevisionsThe required inventory of lead service lines was not completed or submitted on time.EPA: LSL InventoryOct. 17, 2024—Unaddressed
Nitrate-NitriteA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2017 to Dec. 31, 201712 MG/LResolved
Nitrate-NitriteA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2017 to Sept. 30, 201714 MG/LResolved
Nitrate-NitriteA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2017 to June 30, 201712 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 3 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Nitrate, uranium, arsenic, total trihalomethanes (TTHM), fluoride, chromium (total) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of San Juan Bautista’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 Jan. 26, 2020 to March 23, 2026.

Testing your own tap

City of San Juan Bautista’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 City of San Juan Bautista serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Monterey County Consolidated Environmental Laboratory

    Salinas, CA · about 11 miles

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

    (831) 755-4516

  • CM Analytical, Inc.

    Gilroy, CA · about 12 miles

    Certified for bacteria

    (408) 848-3619

  • Bracewell Engineering, Inc.

    Morgan Hill, CA · about 22 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (669) 258-5821

All 145 certified labs for California

Sources

PWSID CA3510002. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in San Benito County

All California utilities

What to do next