us-water-quality-data 2026.4.26

U.S. water quality and home safety data by ZIP code — violations, lead/copper, radon, PFAS, flood risk, home values, remediation costs from 50+ federal sources

us-water-quality-data

U.S. water quality data by ZIP code, packaged for Python. Includes violation history, lead/copper levels, radon zone classification, and Home Safety Scores for 3,500+ ZIP codes, sourced from the EPA Safe Drinking Water Information System (SDWIS).

Install

pip install us-water-quality-data

Quick Start

import us_water_quality_data as water

# Lookup a specific ZIP code
record = water.lookup("10001")
print(record)
# {'zip': '10001', 'city': 'New York', 'state': 'NY',
#  'home_safety_score': 36, 'home_safety_grade': 'F',
#  'total_violations': 7, 'lead_level_mg_l': 0.01, ...}

# All ZIP codes in California
ca = water.get_state("CA")
print(f"{len(ca)} ZIP codes in CA")

# 10 worst scores in the country
worst = water.get_worst(10)
for z in worst:
    print(f"{z['zip']} {z['city']}, {z['state']}: {z['home_safety_score']}")

# 10 best scores
best = water.get_best(10)

# All states in the dataset
print(water.states())  # ['AK', 'AL', 'AR', ...]

# Total ZIP codes
print(water.count())  # 1990+

# Search by city
chicago = water.search_city("chicago")

# Dataset metadata
print(water.meta["updated"])        # '2026-03-17'
print(water.meta["total_zips"])     # 1990
print(water.meta["states_covered"]) # 51

API Reference

lookup(zip_code: str) -> dict | None

Lookup water quality data for a specific ZIP code. Zero-pads short codes automatically.

water.lookup("10001")   # dict
water.lookup("00000")   # None
water.lookup("6001")    # same as "06001"

get_state(state: str) -> list[dict]

Get all ZIP records for a given state. Case-insensitive.

water.get_state("CA")   # all California ZIPs
water.get_state("ny")   # works too

get_worst(n: int = 10) -> list[dict]

Get the ZIP codes with the worst (lowest) Home Safety Scores, sorted ascending.

get_best(n: int = 10) -> list[dict]

Get the ZIP codes with the best (highest) Home Safety Scores, sorted descending.

states() -> list[str]

Get a sorted list of all unique 2-letter state abbreviations in the dataset.

count() -> int

Get the total number of ZIP codes in the dataset.

zips() -> list[str]

Get all ZIP codes in the dataset as a list of strings.

search_city(city: str) -> list[dict]

Search ZIP codes by city name (case-insensitive partial match).

water.search_city("chicago")     # all Chicago ZIPs
water.search_city("san fran")    # partial match works

meta

Dataset metadata as a dict-like object.

water.meta["name"]            # 'ZipCheckup U.S. Water Quality Dataset'
water.meta["license"]         # 'CC-BY-4.0'
water.meta["source"]          # 'U.S. EPA Safe Drinking Water Information System (SDWIS)'
water.meta["updated"]         # '2026-03-17'
water.meta["total_zips"]      # number of ZIPs
water.meta["states_covered"]  # number of states
water.meta["fields"]          # dict of field name -> description

Data Fields

Field	Type	Description
zip	str	5-digit U.S. ZIP code
city	str	City name
state	str	2-letter state abbreviation
home_safety_score	int|None	Composite score 0-100
home_safety_grade	str	Letter grade: A / B / C / D / F
total_violations	int	Total violations in past 5 years
health_violations	int	Health-based violations in past 5 years
unresolved_violations	int	Currently unresolved violations
contaminant_count	int	Distinct health-based contaminants
health_contaminant_names	str	Semicolon-separated contaminant names
lead_level_mg_l	float|None	90th percentile lead level (mg/L)
copper_level_mg_l	float|None	90th percentile copper level (mg/L)
radon_zone	int|None	EPA radon zone: 1 (highest) to 3 (lowest)
water_source	str	SW = Surface Water, GW = Groundwater
system_name	str	Primary water system name
pwsid	str	EPA Public Water System ID
population	int|None	Population served
latitude	float	ZIP centroid latitude
longitude	float	ZIP centroid longitude

Coverage

• ZIP codes: 3,500+ (growing with each release)
• States: All 50 U.S. states + D.C.
• Violation window: Rolling 5 years
• Update frequency: New versions published with each dataset refresh

Data Source

All data is derived from the EPA Safe Drinking Water Information System (SDWIS). Lead and copper levels come from EPA Lead and Copper Rule (LCR) sampling. Radon zones are county-level EPA classifications.

Home Safety Score is a composite 0-100 score that penalizes health-based violations, unresolved violations, lead exceedances, and contaminant count. Methodology: zipcheckup.com/about/home-safety-score/

Also Available

• npm package: us-water-quality-data (Node.js / TypeScript)
• Live site: zipcheckup.com -- free water quality reports by ZIP
• Open dataset (CSV/JSON): zipcheckup.com/data/
• API: api.zipcheckup.com/v1/

License

Data: CC BY 4.0. Code: MIT.

Data by ZipCheckup.com -- sourced from EPA SDWIS.