Skip to content
TapBuff
ZIP

Gowc South Monroe WS

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

Serves
7,335 people
Connections
2,445
Water source
Groundwater
Based in
West Monroe, LA
County
Ouachita Parish
Owner
Private
The 4 ZIP codes it serves

71201, 71202, 71203, 71209

The short answer

1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Total trihalomethanes (TTHM), above the legal limit. 12 health-based violations since 2016.

What handles it

What was found

PFAS and lithium: EPA UCMR 5, samples taken from May 5, 2025 to Nov. 3, 2025.

Lead and copper: EPA SDWIS monitoring periods ending 2010 to 2026.

Total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate: Louisiana’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2022, with EPA’s 2012 to 2019 file for earlier years.

Arsenic, fluoride, chromium (total) and uranium: EPA’s compliance monitoring file, samples taken from Nov. 13, 2012 to April 9, 2018. Newer results are in the utility’s annual water quality report.

PFAS: None of the six PFAS in EPA’s 2024 drinking water rule was found in this utility’s samples. None of the other 23 PFAS tested for was found either.

EPA’s 2024 PFAS rule, compound by compound

PFASEPA’s limitResult
PFOA4.0 pptNot foundNot found in any of 2 samples, below 4 ppt
PFOS4.0 pptNot foundNot found in any of 2 samples, below 4 ppt
PFHxS10 pptNot foundNot found in any of 2 samples, below 3 ppt
PFNA10 pptNot foundNot found in any of 2 samples, below 4 ppt
HFPO-DA (GenX)10 pptNot foundNot found in any of 2 samples, below 5 ppt
PFBSIndex onlyNot foundNot found in any of 2 samples, below 3 ppt
Hazard IndexPFHxS, PFNA, HFPO-DA and PFBS together1Doesn’t applyDoesn’t apply: no sampling location found two or more of the four
Results from EPA’s UCMR 5 sampling. “Below” is the lab’s reporting level: a result under it reads as not found, which is not the same as zero. The limits are EPA’s 2024 rule, with compliance due from 2029; EPA has since proposed changes to some of them, explained on each compound’s page. PFBS has no limit of its own and counts only toward the Hazard Index, which adds up the four, each against EPA’s health-based level, from each sampling location’s average, as EPA’s UCMR 5 summary does. It counts only where two or more of the four were found, and is above the limit from 1.5.

Above the legal limit1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

55ppb

Highest yearly average, 2020 to 2022

Averaged by year, the highest was 55 ppb, in 2022, below EPA’s legal limit of 80 ppb. That was also the latest year on file. EPA judges this limit at each sampling point, and recorded violations for total trihalomethanes (TTHM) at this utility in 2020, 2022 and 2023. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 74 ppb, in 2017, and EPA recorded violations in 2014, 2015, 2017, 2018 and 2019.

What handles it

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

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

2.0ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 2.0 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

Arsenic

Comes from the source

Above the health goal

0.25ppb

Highest yearly average, 2012 to 2018

Averaged by year, the highest was 0.25 ppb, in 2018: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 0.5 ppb. That was also the latest year on file.

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

Lithium

Comes from the source

At EPA’s benchmark, as EPA rounds

11.7ppb

Highest sample, Nov. 3, 2025; found in 2 of 2

The highest sample was 11.7 ppb. As EPA rounds results, that is at EPA’s health reference level of 10 ppb, not above it: EPA counts a result as above it from 15 ppb.

What handles it

No certification claim covers this compound yet.

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

21.1ppb

Highest yearly average, 2020 to 2022

Averaged by year, the highest was 21.1 ppb, in 2022, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 19.5 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.33ppm

Highest yearly average, 2012 to 2018

2018 average: 0.32 ppm

Averaged by year, the highest was 0.33 ppm, in 2012, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.4 ppm. In 2018, the latest year on file, its two samples averaged 0.32 ppm.

What handles it

Utilities above EPA’s PFAS limits, state by state
32 compounds tested and not foundIncluding all six PFAS in EPA’s 2024 rule. Below the reporting level in every sample. Not found is not the same as zero.

From routine monitoring

  • Chromium (total)
  • Nitrate
  • Uranium

PFAS and lithium, from EPA’s UCMR 5 sampling

  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFBA
  • PFBS
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpA
  • PFHpS
  • PFHxA
  • PFHxS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOA
  • PFOS
  • PFPeA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

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, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Total trihalomethanes (TTHM), Lead, Arsenic

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

  • NSF/ANSI 58

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

    For: Total trihalomethanes (TTHM), Lead, Arsenic

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

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

The best reverse osmosis systems, ranked

Disinfectant

Gowc South Monroe WS reported disinfecting with chlorine, not chloramine, at its one sampling point, in its 2025 sampling for EPA.

Chlorine leaves water that sits out for a few days, CDC says. A filter certified for it carries a chlorine claim under NSF/ANSI 42; a shower filter, a free chlorine claim under NSF/ANSI 177. This is what the utility reported for that sampling. Its annual water quality report says what it uses now.

Chlorine vs. chloramineShower filters, by what their listings cover

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2023 to March 31, 20230.084 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 20220.081 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2022 to Sept. 30, 20220.085 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 20200.093 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 20190.095 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20190.092 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2019 to June 30, 20190.1 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2019 to March 31, 20190.084 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2018 to Dec. 31, 20180.087 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2018 to Sept. 30, 201893 UG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2018 to March 31, 2018101 UG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2017 to Dec. 31, 2017113 UG/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) and nitrate results here are Louisiana’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Arsenic, fluoride, chromium (total) and uranium come from EPA’s file alone, which ends in 2019. Gowc South Monroe WS’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 samples are from May 5, 2025 to Nov. 3, 2025; CDC’s yearly averages for Louisiana cover 2020 to 2022; EPA’s compliance samples are from Nov. 13, 2012 to April 9, 2018.

Testing your own tap

Gowc South Monroe WS’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 Louisiana certifies.

No lab Louisiana certifies is within 75 miles of the area Gowc South Monroe WS serves on the state’s list. Some take samples by mail; the state’s page lists them all.

All 48 certified labs for Louisiana

Sources

PWSID LA1073046. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Ouachita Parish

All Louisiana utilities

What to do next