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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
1,215 people
Connections
66
Water source
Surface water
Based in
El Centro, CA
County
Imperial
Owner
Local government
Hardness
Very hard
The ZIP code it serves

92231

The short answer

2 results are above EPA’s legal limit, and 1 more is above the health goal. The worst: Haloacetic acids (HAA5), above the legal limit. 2 health-based violations since 2016.

What handles it

What was found

Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, chromium (total), fluoride and nitrate: California’s own results, samples taken from Feb. 11, 2020 to April 22, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit2

Haloacetic acids (HAA5)

Forms or is added in treatment

Above the legal limit

63.2ppb

Highest yearly average, 2020 to 2025

2025 average: 43.6 ppb

Averaged by year, the highest was 63.2 ppb, in 2020, above EPA’s legal limit of 60 ppb. Its highest single sample was 73 ppb. In 2025, the latest year on file, its 12 samples averaged 43.6 ppb. EPA recorded a violation for haloacetic acids (HAA5) at this utility in 2021. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 73.5 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

70.4ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 70.4 ppb, in 2025, below EPA’s legal limit of 80 ppb. Its highest single sample was 140 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. EPA judges this limit at each sampling point, and recorded a violation for total trihalomethanes (TTHM) at this utility in 2021. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 34.7 ppb, in 2019, and EPA recorded a violation in 2013.

What handles it

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

Above the health goal1

Arsenic

Comes from the source

Above the health goal

2.5ppb

Highest yearly average, 2020 to 2026

2026, one sample: 2.4 ppb

Averaged by year, the highest was 2.5 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2026, the latest year on file, its one sample was 2.4 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.7 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”

Below EPA’s limits3

Chromium (total)

Comes from the source

Below EPA’s limits

70ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 70 ppb, in 2023, below EPA’s legal limit of 100 ppb. Its highest single sample was 140 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. EPA recorded no violation for chromium (total) at this utility since 2020.

What handles it

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.41ppm

Highest yearly average, 2020 to 2026

2026, one sample: 0.37 ppm

Averaged by year, the highest was 0.41 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2026, the latest year on file, its one sample was 0.37 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.37 ppm, in 2018.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.43ppm

Highest sample; found in 1 of 8

2026: not found

The highest sample, in 2025, was 0.43 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, it wasn’t found in its one sample.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
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: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Arsenic

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

  • NSF/ANSI 58

    Claims: Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Arsenic

    Other certifiers’ wording: 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 330 mg/L (19.3 grains per gallon), across 2 sampling points, 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 19.3 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, AverageApril 1, 2021 to June 30, 202189 UG/LResolved
Total Haloacetic Acids (HAA5)The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2021 to March 31, 202161.5 UG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What this report can’t tell you

  • Everything else. Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, chromium (total), fluoride and nitrate results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Gateway’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. 11, 2020 to April 22, 2026.

Testing your own tap

Gateway’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 Gateway serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Babcock Laboratories, Inc.

    El Centro, CA · about 7 miles

    Certified for bacteria

    (951) 653-3351

  • Imperial County Public Health Laboratory

    El Centro, CA · about 7 miles

    Certified for bacteria

    (442) 265-1427

  • Brawley Analytical, Inc.

    Brawley, CA · about 20 miles

    Certified for bacteria, minerals and other inorganics

    (760) 623-1556

All 145 certified labs for California

Sources

PWSID CA1300018. Rebuilt from EPA data on Oct. 18, 2026.

Also in Imperial County

All California utilities

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