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United Water System water quality report, rewritten

Serves
4,446
Connections
1,494
Water source
Groundwater
Based in
Arnaudville, LA
County
St. Martin Parish
Owner
Private
The 13 ZIP codes it serves

70501, 70506, 70508, 70512, 70517, 70520, 70521, 70592, 70714, 70786, 70809, 71435, 77494

PWSID LA1099009 · EPA data

Read this first

  • Copper (above the health goal) In the latest period, 9 in 10 homes sampled were at or below 2.1 ppm, above the 1.3 ppm action level.
  • Lithium (above EPA’s health benchmark) was found in one of 2 samples, highest 11.2 ppb. Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.
  • Lead (above the health goal) In the latest period, 9 in 10 homes sampled were at or below 2.0 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

17 health-based violations since 2016. Details are below.

What handles it

What was found

Highlighted: above the health goal, or EPA’s health benchmark where there is no goal. Circled: above the legal limit in at least one sample, or the action level. Every scale puts that line at its middle.

PFAS and lithium: EPA UCMR 5, samples taken from Aug. 7, 2024 to Feb. 3, 2025. Each blue tick on a scale is one sample where it was found.

Lead and copper: EPA SDWIS monitoring periods ending 2010 to 2020. The pointer marks the latest period; each blue tick is an earlier one.

Copper (above the health goal)

Comes from pipes, often your own

2.1 (above the action level)ppm

90th percentile, 2020

In the latest period, 9 in 10 homes sampled were at or below 2.1 ppm, above the 1.3 ppm action level.

What handles it

11.2ppb

Highest of 2 samples; found in one

Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

What handles it

No certification claim covers this compound yet.

Lead (above the health goal)

Comes from pipes, often your own

2.0ppb

90th percentile, 2023

In the latest period, 9 in 10 homes sampled were at or below 2.0 ppb, below the 15 ppb action level. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Tested and not found

Below EPA’s minimum reporting level in every sample taken from Aug. 7, 2024 to Feb. 3, 2025. Not found means not measured above that level, which is not the same as zero.

All 29 compounds tested and not found
  • 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

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 20220.011 MG/LResolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMay 24, 2022—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMay 24, 2022—Resolved
Groundwater RuleA significant problem found in a state inspection was not fixed on time.EPA: Failure To Address DeficiencyMay 24, 2022—Resolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2020 to June 30, 20200.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 20200.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 20190.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20190.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2019 to June 30, 20190.012 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2019 to March 31, 20190.013 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2018 to Dec. 31, 20180.014 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2018 to Sept. 30, 20180.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2018 to March 31, 20180.012 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2017 to Dec. 31, 20170.012 MG/LResolved
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationJuly 11, 2017—Resolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2017 to Sept. 30, 20170.011 MG/LResolved
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 20170.011 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 7 monitoring or reporting violations not shown.

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, Lead Reduction

    For: Copper, Lead

  • NSF/ANSI 58

    Claims: Copper Reduction, Lead Reduction

    For: Copper, 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.

Compare five-year costs

Filters with those claims on a certifier’s listing

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

What this report cannot tell you

  • Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in United Water System’s own annual report, which it must send you every year.
  • 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.
  • Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from Aug. 7, 2024 to Feb. 3, 2025.

Other Louisiana utilities

All Louisiana utilities

Sources

What to do next

  • Read up on the 3 marked results

    What each one does to health, where it comes from, and the certification claim that addresses it.

    Start with Copper

  • Get the utility’s own report

    United Water System must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

    How to read it

  • Test your own tap for lead

    Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.

    Lead in your water: what to do

  • Compare certified filters

    What the filters certified for these results cost over five years, cartridges included.

    Compare five-year costs