DeKalb County, AL
drinking water quality
73,122 residents · 6 public water systems · 15 ZIP codes
EPA sampled 3 of 6 public water systems here, together serving about 76,122 people. The highest reading was PFOA at 52.5 ng/L at Collinsville Water Works. 2 of the sampled systems were above a federal limit. Last sampled 8/5/2025.
What was found
| Compound | Highest result | Federal limit | Ratio |
|---|---|---|---|
| PFOA | 52.5 ng/L | 4 ng/L | 13.1× |
| PFOS | 6.6 ng/L | 4 ng/L | 1.6× |
Also detected, with no federal limit set: PFHpA (6.9 ng/L), PFHxA (6.8 ng/L), PFPeA (4.7 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 DeKalb County
35961 · 35962 · 35963 · 35967 · 35968 · 35971 · 35974 · 35975 · 35978 · 35979 · 35981 · 35984 · 35986 · 35988 · 35989
Readings are county-level, so every ZIP here shares the figure above. Search your ZIP on the map to see it in context.