Head-to-head water quality

Bryn Mawr, PA vs Houston, TX

Side-by-side water quality comparison: Bryn Mawr (Grade F) vs Houston (Grade F). Lead, PFAS, violations, and source-water contamination

Score breakdown

Each factor is shown as raw points (out of the maximum). Higher = better.

Factor

Bryn Mawr

Houston

Better

Violations subscore / 45

0.0

Tie

Lead/Copper subscore / 20

16.0

Tie

Contaminant subscore / 20

4.2

2.8

Bryn Mawr

Compliance subscore / 10

10.0

5.0

Bryn Mawr

Source subscore / 5

4.0

Tie

Lead & copper at the tap

Lead and Copper Rule (LCR) 90th-percentile readings — the value that 10% of sampled homes exceed.

Factor

Bryn Mawr

Houston

Better

Lead 90th-percentile (latest) · EPA action level: 15 µg/L

0.0 µg/L

Tie

Copper 90th-percentile (latest) · EPA action level: 1.3 mg/L

1.4 mg/L

1.5 mg/L

Bryn Mawr

PFAS — "forever chemicals"

UCMR 5 testing, 2023–2025. Federal MCLs: PFOA + PFOS = 4 ng/L; HFPO-DA = 10 ng/L.

Factor

Bryn Mawr

Houston

Better

PFAS analytes detected

10 of 30

Tie

PFAS exceeds federal MCL

Yes

Tie

PFAS hazard index · Sum of (max/MCL) across detected analytes; > 1 indicates exceedance

9.43

3.42

Houston

Violation history

SDWA enforcement actions — fewer is better.

Factor

Bryn Mawr

Houston

Better

Violations (last 5 years)

147

2,071

Bryn Mawr

Health-based violations (total)

929

Bryn Mawr

Unresolved violations

3,572

Bryn Mawr

Other contaminants tested

UCMR rounds 1–4 + UCMR 5 lithium. Maxima where data exists; "—" means not tested.

Factor

Bryn Mawr

Houston

Better

Chromium-6 (max)

2.60 µg/L

6.66 µg/L

Bryn Mawr

HAA5 (avg)

25.99 µg/L

18.35 µg/L

Houston

Manganese (max)

81.00 µg/L

158.90 µg/L

Bryn Mawr

Strontium (max)

817.00 µg/L

948.00 µg/L

Bryn Mawr

1,4-Dioxane (max)

2.20 µg/L

1.15 µg/L

Houston

NDMA (max)

15.00 ng/L

43.30 ng/L

Bryn Mawr

Vanadium (max)

2.10 µg/L

16.00 µg/L

Bryn Mawr

Chlorate (max)

838.00 µg/L

13600.00 µg/L

Bryn Mawr

Molybdenum (max)

8.50 µg/L

12.60 µg/L

Bryn Mawr

Industrial proximity

Superfund National Priorities List + Toxic Release Inventory facilities within 10 miles of the city centroid.

Factor

Bryn Mawr

Houston

Better

Superfund sites within 10 mi

Houston

TRI lbs to surface water within 10 mi (2023)

1,981,876

Bryn Mawr

System size & source

Factor

Bryn Mawr

Houston

Population served

1.1M

5.9M

—

Water source

Surface water

—

Number of water systems

719

—

See the full reports

Full report

Bryn Mawr, PA water quality

Grade F · 1.1M served

Full report

Houston, TX water quality

Grade F · 5.9M served

All cities in Pennsylvania → All cities in Texas →

Frequently asked

Which has better water — Bryn Mawr or Houston?

Bryn Mawr, PA scores higher (34.2 vs 27.8) on WaterVerge's 100-point methodology, earning a Grade F compared to Houston's Grade F. 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.