Head-to-head water quality
Chesterfield, MO vs Smithtown (T), NY
Side-by-side water quality comparison: Chesterfield (Grade B-) vs Smithtown (T) (Grade B). Lead, PFAS, violations, and source-water contamination
Score breakdown
Each factor is shown as raw points (out of the maximum). Higher = better.
Factor
Chesterfield
Smithtown (T)
Better
Violations subscore / 45
34.4
37.9
Smithtown (T)
Lead/Copper subscore / 20
20.0
20.0
Tie
Contaminant subscore / 20
13.4
7.8
Chesterfield
Compliance subscore / 10
3.0
8.0
Smithtown (T)
Source subscore / 5
4.0
5.0
Smithtown (T)
Lead & copper at the tap
Lead and Copper Rule (LCR) 90th-percentile readings — the value that 10% of sampled homes exceed.
Factor
Chesterfield
Smithtown (T)
Better
Lead 90th-percentile (latest) · EPA action level: 15 µg/L
0.0 µg/L
0.0 µg/L
Chesterfield
Copper 90th-percentile (latest) · EPA action level: 1.3 mg/L
—
—
—
PFAS — "forever chemicals"
UCMR 5 testing, 2023–2025. Federal MCLs: PFOA + PFOS = 4 ng/L; HFPO-DA = 10 ng/L.
Factor
Chesterfield
Smithtown (T)
Better
PFAS analytes detected
2 of 30
10 of 30
Chesterfield
PFAS exceeds federal MCL
No
Yes
Chesterfield
PFAS hazard index · Sum of (max/MCL) across detected analytes; > 1 indicates exceedance
—
5.97
Smithtown (T)
Violation history
SDWA enforcement actions — fewer is better.
Factor
Chesterfield
Smithtown (T)
Better
Violations (last 5 years)
0
1
Chesterfield
Health-based violations (total)
11
5
Smithtown (T)
Unresolved violations
34
3
Smithtown (T)
Other contaminants tested
UCMR rounds 1–4 + UCMR 5 lithium. Maxima where data exists; "—" means not tested.
Factor
Chesterfield
Smithtown (T)
Better
Chromium-6 (max)
1.55 µg/L
5.59 µg/L
Chesterfield
HAA5 (avg)
20.48 µg/L
0.76 µg/L
Smithtown (T)
Manganese (max)
4.90 µg/L
419.00 µg/L
Chesterfield
Strontium (max)
220.30 µg/L
169.00 µg/L
Smithtown (T)
1,4-Dioxane (max)
0.15 µg/L
4.34 µg/L
Chesterfield
NDMA (max)
9.30 ng/L
13.43 ng/L
Chesterfield
Perchlorate (max)
—
12.10 µg/L
Smithtown (T)
Vanadium (max)
4.90 µg/L
6.97 µg/L
Chesterfield
Chlorate (max)
370.00 µg/L
386.00 µg/L
Chesterfield
Molybdenum (max)
4.20 µg/L
1.18 µg/L
Smithtown (T)
Industrial proximity
Superfund National Priorities List + Toxic Release Inventory facilities within 10 miles of the city centroid.
Factor
Chesterfield
Smithtown (T)
Better
Superfund sites within 10 mi
4
0
Smithtown (T)
TRI lbs to surface water within 10 mi (2023)
214
0
Smithtown (T)
System size & source
Factor
Chesterfield
Smithtown (T)
Population served
1.1M
1.1M
—
Water source
Surface water
Groundwater
—
Number of water systems
3
2
—
See the full reports
Frequently asked
Which has better water — Chesterfield or Smithtown (T)?
Smithtown (T), NY scores higher (78.8 vs 74.8) on WaterVerge's 100-point methodology, earning a Grade B compared to Chesterfield's Grade B-. The score combines violation history, lead and copper levels, contaminant testing, monitoring compliance, and source-water type.
How is the WaterVerge water quality score calculated?
The grade combines five subscores: violation history (45 pts, weighted by recency and health-based severity), lead/copper 90th-percentile vs EPA action levels (20 pts), contaminant testing including PFAS, chromium-6, HAA5, NDMA, perchlorate, and Superfund/TRI proximity (20 pts), monitoring compliance (10 pts), and water-source-type risk (5 pts). Full methodology at /about/methodology.
Where does this water quality data come from?
From the EPA's public records: the SDWIS bulk download (violations + system info), UCMR rounds 1–5 (unregulated contaminant testing including PFAS, chromium-6, HAA5, NDMA, perchlorate, vanadium, lithium), the EPA Toxic Release Inventory (industrial polluters), the Superfund National Priorities List, the USGS Powell Domestic-Well Database (private-well chemistry), and the CDC Community Water Fluoridation system. Data is refreshed quarterly.