A
94

Excellent Water Quality

Madisonville, LA 70447

Saint Tammany County · Population served: 20,197 · Data updated March 2026

Water Systems Serving This Area

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MADISONVILLE WATER SUPPLY
Groundwater · Pop. 871
PWSID: LA1103022
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ST TAM PARISH- BEDICO -FAUBOURG-COQUILLE
Groundwater · Pop. 18,372
PWSID: LA1103149
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LEWISBURG ESTATES
Groundwater · Pop. 60
PWSID: LA1103156
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VILLAGES OF BOCAGE- MADISONVILLE
Groundwater · Pop. 894
PWSID: LA1103195

Contaminants Detected

ContaminantDetected LevelEPA MCLHealth GuidelineStatus
Lead
2.0
15 ppb 1 ppb Warning

Violation History (Last 5 Years)

1Total (5yr)
0Health-Based
0Major

Water Quality Summary

Understanding Your Water in Madisonville

Tap water quality in Madisonville, Louisiana (70447) receives an overall grade of A (Excellent) with a score of 94 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is 16 points above the Louisiana state average of 78. Compared to the national average (75), this area performs significantly better. The area is served by 4 water systems providing water to approximately 20,197 people, using groundwater sources. Testing has found elevated levels of Lead that warrant attention.

Your Score 94/100 A
vs State 16 pts above Louisiana avg (78)
vs National 19 pts above national avg (75)

What a Grade A Means

A score of 94/100 means the water supply in Madisonville, LA meets or exceeds all EPA standards with minimal issues. Contaminant levels are well within safe limits, and the water system has maintained a strong compliance record. While no water supply is guaranteed perfect at the tap due to household plumbing, this is among the best-scoring areas in the country.

Groundwater: drawn from underground aquifers via wells

Health Information

What These Contaminants Mean for You

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Lead in Your Water

Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.

Health Effects

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.

Common Sources

Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.

What You Can Do

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.

Common Questions

Frequently Asked Questions

Based on EPA data, tap water in Madisonville, Louisiana receives a grade of A (Excellent) with a score of 94/100. This indicates the water meets federal standards and has relatively few concerns. However, individual homes may still have localized issues such as lead from old plumbing.

ZIP code 70447 is served by 4 water systems using groundwater sources, providing water to approximately 20,197 people. Groundwater is naturally filtered through rock and soil, often requiring less treatment. However, it can be vulnerable to contamination from underground sources like naturally occurring arsenic, nitrates from agriculture, or PFAS from industrial sites.

Lead was detected at 2.0 ppb in Madisonville, Louisiana. While this is below the EPA action level of 15 ppb, it exceeds the health guideline of 1 ppb recommended by health organizations. Consider a certified lead filter, especially if you have young children.

No PFAS ("forever chemicals") were detected in water systems serving Madisonville, Louisiana during the most recent EPA monitoring period (UCMR5). However, not all water systems have been tested for all PFAS compounds, and new contamination can occur over time.

Water systems serving Madisonville, Louisiana have received 1 violation in the last 5 years. 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), residents in Madisonville, Louisiana should consider: NSF/ANSI 53 certified filter — specifically rated for lead reduction. Pitcher filters (like Brita Longlast or PUR) and under-sink systems both work. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.

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