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Llano Grande Lake Park East

What EPA’s and Texas’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
1,300 people
Connections
701
Water source
Surface water bought from another system
Based in
Mercedes, TX
County
Hidalgo
Owner
Private
The ZIP code it serves

78570

The short answer

1 result is above EPA’s legal limit. The worst: Copper, above the action level. 6 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2018 to 2021.

Total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate: Texas’s own results, samples taken from March 9, 2020 to Aug. 19, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Copper

Comes from pipes, often your own

Above the action level

1.7ppm

90th percentile, 2021

In the latest period, 9 in 10 homes sampled were at or below 1.7 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Below EPA’s limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

61.2ppb

Highest yearly average, 2020 to 2026

2026 average: 39.7 ppb

Averaged by year, the highest was 61.2 ppb, in 2021, below EPA’s legal limit of 80 ppb. Its highest single sample was 117 ppb. In 2026, the latest year on file, its six samples averaged 39.7 ppb. EPA recorded no violation for total trihalomethanes (TTHM) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 87.6 ppb, in 2012, and EPA recorded violations in 2013 and 2015.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

20.9ppb

Highest yearly average, 2020 to 2026

2026 average: 15.2 ppb

Averaged by year, the highest was 20.9 ppb, in 2020, below EPA’s legal limit of 60 ppb. Its highest single sample was 43.2 ppb. In 2026, the latest year on file, its six samples averaged 15.2 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 23.6 ppb, in 2012.

What handles it

No certification claim covers this compound yet.

Nitrate

Comes from the source

Below EPA’s limits

1.8ppm

Highest sample; found in 6 of 6

2025, one sample: 0.27 ppm

The highest sample, in 2022, was 1.8 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, its one sample was 0.27 ppm.

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.”

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

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationOct. 1, 2022—Unaddressed
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationApril 1, 2022—Unaddressed
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationMarch 31, 2022—Unaddressed
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationOct. 1, 2019—Resolved
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationApril 1, 2019—Resolved
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationMarch 31, 2019—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 52 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate results here are Texas’s own from 2020 on, with EPA’s national file for 2012 to 2019. Llano Grande Lake Park East’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; Texas’s results run from March 9, 2020 to Aug. 19, 2026.

Testing your own tap

Llano Grande Lake Park East’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 Texas certifies.

The lab Texas certifies closest to the area Llano Grande Lake Park East serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Texas Department of State Health Services South Texas Laboratory

    Harlingen, TX · about 10 miles

    Certified for bacteria

    (956) 364-8746

Texas Well Owner Network, Texas A&M AgriLife Extension: Well Informed screening events, where well owners bring in water samples to be screened for common contaminants, followed by an hour-long session explaining the results. Upcoming events are on the network's calendar. Trainings, Texas Well Owner Network.

All 80 certified labs for Texas

Sources

PWSID TX1080034. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Hidalgo County

All Texas utilities

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