Side-by-side water intelligence
Compare water intelligence.
Put cities, states, water systems, or ZIP codes next to each other and read the measurable differences. PurityMap never combines them into a single winner or safety verdict.
CompareUp to 3, side by side. No overall score, rank or verdict. Missing evidence stays missing.
Water systemNORWALK - CITY, WATER DEPT.CA1910191 · CA
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Identity
Side by side
BasisEach column shows its latest public record. Sample years can differ between columns, so compare with care.
| Field | NORWALK - CITY, WATER DEPT. |
|---|---|
| System | NORWALK - CITY, WATER DEPT. |
| Place | Norwalk |
| Population served | 20,283 |
| Source type | Surface Water |
| Record updated | 2026-09-16 |
| Findings on record | 31 |
| Above a listed reference | 3 |
Substance by substance
Where the records differ
Detected results first. Each cell keeps the published result and its record state. “No record” is different from “not detected”.
- Above a reference
- Detected, within reference
- Not detected
- No record
| Substance · reference | NORWALK - CITY, WATER DEPT. |
|---|---|
| Perfluorooctanoic acid (PFOA)4.0 ng/L federal MCL (2024) | 5.2ng/LAbove a reference |
| Perfluorooctanesulfonic acid (PFOS)4.0 ng/L federal MCL (2024) | 26ng/LAbove a reference |
| Lithium10.0 µg/L EPA health reference level (screening, not a legal limit) | 59µg/LAbove a reference |
| Perfluorobutanoic acid (PFBA)No federal or state limit; shown for transparency | 5.6ng/LDetected, no limit |
| Perfluorohexanesulfonic acid (PFHxS)10.0 ng/L federal MCL (2024) | 7.6ng/LDetected, within reference |
| Perfluoropentanoic acid (PFPeA)No federal or state limit; shown for transparency | 3.4ng/LDetected, no limit |
Comparison boundary
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Different monitoring periods, source types and coverage can limit direct comparison. Missing evidence stays missing; it is never scored as favourable, and nothing here is combined into an overall rank or safety verdict.