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EPA ID TX1010013 · checked 16 Oct 2026

Houston tap water: what EPA testing found

City of Houston (EPA record: CITY OF HOUSTON) serves 2,970,543 people in TX from surface water. It also sells water to other utilities.

What the data shows

PFAS and lithium (EPA UCMR 5)

2,880 results from 39 sampling points, 6 Feb 2023 to 21 Feb 2025. Averages count results below EPA’s reporting level as zero, as the PFAS rule does. Every number links to EPA’s UCMR 5 Data Finder (search PWSID TX1010013). Limits: EPA PFAS rule.

ContaminantDetected inHighest resultAverageEPA limit
PFOA0 of 96not detected0 ng/L4 ng/L
PFOS0 of 96not detected0 ng/L4 ng/L
PFHxS0 of 96not detected0 ng/L10 ng/L*
PFNA0 of 96not detected0 ng/L10 ng/L*
HFPO-DA0 of 96not detected0 ng/L10 ng/L*
PFBA9 of 9610.6 ng/L0.67 ng/Lnone
PFHxA16 of 965.1 ng/L0.62 ng/Lnone
PFPeA11 of 966.7 ng/L0.46 ng/Lnone
6:2 FTS10 of 9642.6 ng/L1.66 ng/Lnone
Lithium69 of 9633.9 µg/L12.4 µg/Lnone (screening level 10 µg/L)

* PFHxS, PFNA and HFPO-DA limits (and the PFAS hazard index) are in the rule, but EPA proposed on 20 May 2026 to rescind them; not final as of 16 Oct 2026. UCMR 5 results are screening data, not compliance results: compliance uses quarterly running averages from 2029. Source file: EPA UCMR 5 occurrence data (dated 15 Oct 2026).

Health-based violations since 2016

Period beganContaminant or ruleViolationMeasuredStatus
1 May 2025Interim Enhanced Surface Water Treatment RuleSingle Turbidity Exceed (Enhanced SWTR)–Returned to Compliance (1 Jul 2025)

Source: EPA SDWIS via Envirofacts and the ECHO report for TX1010013, retrieved 16 Oct 2026.

Hardness

7.9 grains per gallon (average, 2025), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.

Places and ZIP codes served

Houston, Humble, Pasadena, Bellaire, Deer Park, Friendswood, Galena Park, Missouri City, South Houston, Stafford, Sugar Land, Webster.

77002 77003 77004 77005 77006 77007 77008 77009 77010 77011 77012 77013 77014 77015 77016 77017 77018 77019 77020 77021 77022 77023 77024 77025 77026 77027 77028 77029 77030 77031 77032 77033 77034 77035 77036 77037 77038 77040 77041 77042 77043 77044 77045 77046 77047 77048 77049 77050 77051 77053 77054 77055 77056 77057 77059 77060 77061 77063 77064 77067 77071 77072 77073 77074 77075 77076 77077 77078 77079 77080 77081 77082 77083 77084 77085 77086 77087 77088 77089 77090 77091 77092 77093 77094 77096 77098 77099 77338 77346 77396 77401 77477 77489 77498 77503 77504 77506 77536 77546 77547 77587 77598

ZIP codes the system reported to EPA for UCMR 5; place names from GeoNames (CC BY 4.0). A ZIP code can be split between systems.