Madison County, AL
drinking water quality
423,355 residents · 9 public water systems · 22 ZIP codes
EPA sampled 8 of 9 public water systems here, together serving about 606,546 people. The highest reading was PFOS at 9 ng/L at Huntsville Utilities Water Dept.. 3 of the sampled systems were above a federal limit. Last sampled 9/9/2025.
What was found
| Compound | Highest result | Federal limit | Ratio |
|---|---|---|---|
| PFOS | 9 ng/L | 4 ng/L | 2.3× |
| PFOA | 4.7 ng/L | 4 ng/L | 1.2× |
Also detected, with no federal limit set: PFBA (11 ng/L), PFBS (6.2 ng/L), PFPeA (5.3 ng/L), PFHxA (4.4 ng/L).
What this means
PFAS are industrial chemicals that EPA describes as breaking down only very slowly in the environment. In April 2024 EPA set the first enforceable national limits: 4 ng/L for PFOA and PFOS, 10 ng/L for PFHxS, PFNA and GenX.
These figures are county-level and come from EPA’s sampling of public water systems. They describe the worst result found in the county, not what comes out of any particular tap — that depends on which system serves the address, and on the plumbing in the building. A private well is not covered by this programme at all.
ZIP codes in Madison County
35741 · 35748 · 35749 · 35750 · 35757 · 35758 · 35759 · 35760 · 35761 · 35763 · 35773 · 35801 · 35802 · 35803 · 35805 · 35806 · 35808 · 35810 · 35811 · 35816 · 35824 · 35896
Readings are county-level, so every ZIP here shares the figure above. Search your ZIP on the map to see it in context.