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.
How to compare
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- Cities, states, systems or ZIPs
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- Up to 3, side by side
- Read
- Measured differences
No overall score, rank, or safety verdict — missing evidence stays missing.
3 of 3 cities selectedCompare published city records — Purity Score, supplier, source and contaminant findings.
Side-by-side
Scroll sideways on a narrow screen — the field column stays pinned so the rows always line up.
| Comparison field | New York, NY NEW YORK CITY SYSTEM86/100Good | Los Angeles, CA LOS ANGELES-CITY, DEPT. OF WATER & POWER90/100Excellent | Chicago, IL CHICAGO88/100Good |
|---|---|---|---|
| Serving utility | NEW YORK CITY SYSTEM | LOS ANGELES-CITY, DEPT. OF WATER & POWER | CHICAGO |
| Population served | 8,271,000 | 3,875,566 | 2,721,308 |
| Primary source | Surface water (primary source of record in EPA SDWIS). | Surface water (primary source of record in EPA SDWIS). | Surface water (primary source of record in EPA SDWIS). |
| Water hardness | Unknown | 8.2 gpg · Hard | 8.2 gpg · Hard |
| Disinfectant | Unknown | Chloramine | Chlorine |
| Findings above a guideline | 0 | 1 | 1 |
| Record updated | 2026-09-16 | 2026-09-16 | 2026-09-16 |
Substance-by-substance evidence
Each cell keeps the published result and finding state. “No record” is different from “not detected.”
| Substance | New York, NY | Los Angeles, CA | Chicago, IL |
|---|---|---|---|
| Perfluorooctanoic acid (PFOA)Pfas | Non-detectreporting limit 4 ng/L | Non-detectreporting limit 4 ng/L | Non-detectreporting limit 4 ng/L |
| Perfluorooctane sulfonic acid (PFOS)Pfas | Non-detectreporting limit 4 ng/L | Non-detectreporting limit 4 ng/L | Non-detectreporting limit 4 ng/L |
| Perfluorohexane sulfonic acid (PFHxS)Pfas | Non-detectreporting limit 10 ng/L | Non-detectreporting limit 10 ng/L | Non-detectreporting limit 10 ng/L |
| Lead (90th percentile)Metals | Within limit10 µg/L | Within limit3.9 µg/L | Within limit8.8 µg/L |
| Water hardnessCharacteristics | No record | Above limit8.2 gpg | Above limit8.2 gpg |
| Total trihalomethanes (TTHM)Disinfection byproducts | No record | Within limit33.8 ppb | Within limit26.4 ppb |
| Haloacetic acids (HAA5)Disinfection byproducts | No record | Within limit13.4 ppb | Within limit13.8 ppb |
| NitrateInorganics | No record | Within limit0.4 mg/L | No record |
| ArsenicMetals | No record | Within limit0.003 mg/L | No record |
| CopperMetals | No record | Within limit0.529 mg/L | No record |
| FluorideInorganics | No record | Within limit0.7 mg/L | No record |
Comparison boundary
Different monitoring periods, source types and coverage can limit direct comparison. Missing evidence stays missing; it is never scored as favorable, and nothing here is combined into an overall rank or safety verdict.