US Water Score: C
| Contaminant | Detected Level | EPA MCL | Health Guideline | Status |
|---|---|---|---|---|
| Lead |
15.6
|
15 ppb | 1 ppb | |
| Copper |
6280.0
|
1300 ppb | 300 ppb |
UCMR5 occurrence results are screening information, not a finding of regulatory compliance or noncompliance. PFAS rules and compliance dates are evolving.
| Compound | Level | EPA MCL | Health Guideline | Status |
|---|---|---|---|---|
| PFBA | 12.2 ppt | No standard | 500 ppt | No federal MCL shown |
| PFPeA | 3.8 ppt | No standard | — | No federal MCL shown |
| PFHxA | 3.5 ppt | No standard | 400 ppt | No federal MCL shown |
| PFHxS | 3.4 ppt | 10 ppt | 10 ppt | Below comparison value |
| PFBS | 3.0 ppt | 2000 ppt | 100 ppt | Below comparison value |
Water Quality Summary
Tap water quality in Mercedes, Texas (78570) receives an overall grade of C (Fair) with a score of 65 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is 15 points below the Texas state average of 80. The area is served by 4 water systems providing water to approximately 171,195 people, using surface water sources. PFAS testing detected 5 compounds, all below the EPA final MCL values used for comparison. Over the past 5 years, water systems here have accumulated 60 violations, including 7 health-based violations.
A score of 65/100 indicates fair performance in the US Water Score model for Mercedes, TX. The records show noteworthy concerns, such as elevated contaminant levels, violation history, or both. Review the detailed contaminant data and official utility reports before making decisions.
Health Information
Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.
Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.
Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.
If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.
Copper can leach into water from copper plumbing, especially in newer homes or when water is acidic.
Short-term exposure above 1,300 ppb can cause gastrointestinal distress. Long-term exposure may cause liver or kidney damage. People with Wilson's disease are especially vulnerable.
Copper pipes, fittings, and faucets are the most common source. Corrosive (low-pH) water accelerates copper leaching.
If copper levels are elevated, flush pipes by running water for 15–30 seconds before use. Reverse osmosis and distillation systems effectively remove copper.
Common Questions
Mercedes, Texas receives an internal US Water Score grade of C (Fair) with a score of 65/100. Our model found some system-level concerns, such as violation history or elevated contaminant levels. Review your utility's Consumer Confidence Report and consult a qualified professional for household-specific health questions.
ZIP code 78570 is served by 4 water systems using surface water sources, providing water to approximately 171,195 people. Surface water systems are more susceptible to contamination from agricultural runoff, industrial discharge, and weather events, but typically undergo more extensive treatment including filtration and disinfection.
Lead levels in the public-system record for Mercedes, Texas are 15.6 ppb, above the currently applicable EPA action level of 15 ppb. EPA's Lead and Copper Rule Improvements lower that action level to 10 ppb when the new requirements take effect. This system-level result does not measure an individual tap; consider a certified lead-removal filter and independent tap testing.
5 PFAS compounds were detected in water serving Mercedes, Texas, with reported values below the EPA final MCL values used by this site. This comparison is informational: federal compliance timelines and the status of some PFAS standards are still evolving. Activated carbon or reverse osmosis filters can reduce some PFAS when appropriately certified and maintained.
Water systems serving Mercedes, Texas have received 60 violations in the last 5 years, including 7 health-based violations. Violations can range from paperwork issues (monitoring & reporting) to serious health-based violations where contaminant levels exceeded safe limits. Review the violation details above for specifics.
Based on detected contaminants (lead, PFAS, copper), residents in Mercedes, Texas should consider: Reverse osmosis (RO) system — most effective for PFAS, lead, and other contaminants. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.