Head-to-head water quality

Columbus, OH vs Oakland, CA

Side-by-side water quality comparison: Columbus (Grade F) vs Oakland (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

Columbus

Oakland

Better

Violations subscore / 45

0.0

35.1

Oakland

Lead/Copper subscore / 20

16.0

Tie

Contaminant subscore / 20

7.4

14.8

Oakland

Compliance subscore / 10

8.0

Tie

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

Columbus

Oakland

Better

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

0.0 µg/L

Columbus

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

46.0 mg/L

1.8 mg/L

Oakland

PFAS — "forever chemicals"

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

Factor

Columbus

Oakland

Better

PFAS analytes detected

7 of 30

1 of 30

Oakland

PFAS exceeds federal MCL

Yes

Oakland

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

1.80

—

Columbus

Violation history

SDWA enforcement actions — fewer is better.

Factor

Columbus

Oakland

Better

Violations (last 5 years)

Oakland

Health-based violations (total)

Oakland

Unresolved violations

Oakland

Other contaminants tested

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

Factor

Columbus

Oakland

Better

Chromium-6 (max)

0.35 µg/L

0.22 µg/L

Oakland

HAA5 (avg)

16.32 µg/L

34.22 µg/L

Columbus

Manganese (max)

0.48 µg/L

12.70 µg/L

Columbus

Strontium (max)

1300.00 µg/L

320.00 µg/L

Oakland

1,4-Dioxane (max)

0.12 µg/L

—

Columbus

NDMA (max)

—

3.30 ng/L

Oakland

Vanadium (max)

0.69 µg/L

2.40 µg/L

Columbus

Chlorate (max)

370.00 µg/L

480.00 µg/L

Columbus

Molybdenum (max)

12.00 µg/L

1.20 µg/L

Oakland

Industrial proximity

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

Factor

Columbus

Oakland

Better

Superfund sites within 10 mi

Columbus

TRI lbs to surface water within 10 mi (2023)

103

Oakland

System size & source

Factor

Columbus

Oakland

Population served

1.3M

1.4M

—

Water source

Surface water

—

Number of water systems

—

See the full reports

Full report

Columbus, OH water quality

Grade F · 1.3M served

Full report

Oakland, CA water quality

Grade B · 1.4M served

All cities in Ohio → All cities in California →

Frequently asked

Which has better water — Columbus or Oakland?

Oakland, CA scores higher (77.9 vs 35.5) on WaterVerge's 100-point methodology, earning a Grade B compared to Columbus'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.