Check the Setup
- Python 3.10 or newer
- An internet connection
- The requests Python package
Microproduct Data GuideIntermediate
EPA SDWIS Bulk Submission Archive
EPA Safe Drinking Water Act public-system and violation bulk tables for reproducible compliance analysis.
Report a ProblemAt a Glance
- Difficulty
- Intermediate — some data preparation helps
- Size
- Medium · 0.3–5.2 GB
- Formats
- ZIP, CSV
- Access
- Download
- API Key
- Not Required
- Provider
- U.S. Environmental Protection Agency
- Updates
- Quarterly
- Last Verified
- Sep 28, 2026
- Source Type
- Government Source
- Python Syntax Checked
From Source to Product Signal
Test a Product Idea in Four Steps
HouseHunter pins EPA's 2026Q2 SDWIS bulk ZIP, not the ECHO web-service response. Start with a bounded byte range from the current official archive to verify its ZIP member and submission quarter. The current URL may advance; do not use a later quarter as if it were HouseHunter's pinned input.
Access the Data
- 1.Read EPA's bulk-download dictionary and public-domain notice.
- 2.Fetch a bounded first range of the official ZIP and inspect its first member.
- 3.Download and pin the full archive only when you need to join system and violation tables.
3
Run the Python Example
Install the packages, then run the notebook cell.
python -m pip install requests
import csv
import io
import struct
import zlib
import requests
response = requests.get(
"https://echo.epa.gov/files/echodownloads/SDWA_latest_downloads.zip",
headers={"Range": "bytes=0-131071"}, timeout=30,
)
response.raise_for_status()
assert response.status_code == 206, "Server did not honor bounded byte range"
chunk = response.content
header = struct.unpack_from("<IHHHHHIIIHH", chunk)
assert header[0] == 0x04034B50 and header[3] == 8
start = 30 + header[-2] + header[-1]
name = chunk[30:30 + header[-2]].decode()
text = zlib.decompressobj(-15).decompress(chunk[start:]).decode()
rows = csv.DictReader(io.StringIO("\n".join(text.splitlines()[:3])))
print(name, [(row["SUBMISSIONYEARQUARTER"], row["PWSID"]) for row in rows])4
Test a Useful Signal
Check a SDWIS Submission Quarter
Verify the archive's reported quarter before combining public-system tables.
- 01Inspect a bounded archive member and its SUBMISSIONYEARQUARTER values.
- 02Record the archive URL, retrieval time, and hash before full download.
- 03Explain why system records and violation records need quarter-aware joins.
Dataset Details
U.S. Environmental Protection Agency is a government source. Last verified 2026-09-28. Temporal coverage: quarterly submissions, with HouseHunter pinned to 2026Q2.
Domains
Data Types
Tasks
Geography
Provider
U.S. Environmental Protection Agency
Data Terms
EPA-produced data are public domain unless otherwise specified; cite EPA and preserve submission-quarter, system, reporting, and data-quality limitations.