McAllen, TX Water Quality (ZIP 78504)

Quick Answers

Is ZIP 78504 tap water safe to drink? PFAS compounds have been detected in 78504's water at an average of 6.68 ppt across 8 compounds. A certified pitcher filter or reverse osmosis system is recommended, especially for sensitive populations.

What filter should I use in 78504? A reverse osmosis system (NSF/ANSI 58) removes 90%+ of PFAS, lead, and arsenic. For smaller households, a pitcher certified to NSF-53 for PFAS (ZeroWater, PUR PLUS) works. Standard Brita cartridges are not certified for PFAS.

ZIP 78504 Water Quality Summary

EPA testing has detected PFAS "forever chemicals" in the water systems serving ZIP 78504 (McAllen, TX). Monitoring found a peak of 27.2 ppt across 2 systems, averaging 6.68 ppt over 8 detected compounds. These levels come from individual EPA UCMR 5 water samples (2023-2025). The EPA's 4 ppt limit for PFOA and PFOS is enforced on a running annual average, so a sample above it shows real exposure but is not by itself a violation.

Contamination Level: MODERATE – Moderate contamination – PFAS detected at meaningful levels; filtration recommended.

Top Detected Compounds in ZIP 78504

• PFBA: 27.2 ppt (exceeds the EPA 4 ppt limit)
• PFHXA: 12.5 ppt (exceeds the EPA 4 ppt limit)
• PFPEA: 12.3 ppt (exceeds the EPA 4 ppt limit)
• PFOS: 6.8 ppt (exceeds the EPA 4 ppt limit)
• PFHXS: 6.4 ppt

Lead in ZIP 78504 Water

EPA Lead and Copper Rule testing recorded 10 lead samples for the systems serving 78504, with a 90th-percentile high of 0.0023 mg/L (within the EPA 0.015 mg/L action level). There is no safe level of lead for children; homes built before 1986 should use a certified NSF/ANSI 53 lead filter.

EPA Violations Affecting ZIP 78504

The water systems serving 78504 has 1 health-based EPA Safe Drinking Water Act violation on record, including Chlorite. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.

About the Data

Source: EPA UCMR5 monitoring (2023-2025), Lead and Copper Rule samples, and SDWIS violation records tied to the water system that serves 78504 in McAllen, TX.

Beyond water: other exposures in McAllen, TX

Drinking water is one exposure route. These are the other federal datasets that cover ZIP 78504 and Hidalgo County, TX.

Radon risk in Hidalgo County, TX

The EPA places Hidalgo County, TX in Zone 3 - the EPA's lowest-risk category, with a predicted average indoor radon level below 2 pCi/L. Zone maps predict the radon potential of an area from geology and existing indoor readings - they do not describe any individual home. Radon is the leading cause of lung cancer among people who have never smoked, and the only way to know your own level is a test kit.

Lead paint risk in Hidalgo County, TX

Census figures show 19% of homes in Hidalgo County, TX were built before 1980, and 2% before 1950. Lead-based paint was banned for residential use in 1978, so older housing stock is the strongest available proxy for lead-paint exposure. This is a statistic about the county's housing, not a test of any particular property - if your home predates 1980, a lead swab test is the way to check.

Air quality in Hidalgo County, TX

Modelled annual fine-particle pollution (PM2.5) for Hidalgo County, TX averages 9.8 µg/m³, above the EPA's annual PM2.5 standard of 9 µg/m³. PM2.5 is the pollution fraction small enough to reach deep into the lungs. These are CDC modelled estimates for the county as a whole, not a reading taken at this ZIP code.