Provenance record · public source
Safe Drinking Water Information System (SDWIS) — Lead & Copper Rule 90th-percentile results
90th-percentile lead results reported to SDWIS under the Lead & Copper Rule.
What this source covers
- Coverage
- U.S. public water systems · Lead & Copper Rule monitoring (records since 1992)
- Used by PurityMap
- Lead and copper 90th-percentile results, one per monitoring round
- Document type
- State SDWIS Compliance Record
What it can’t tell you
- A 90th-percentile summary describes sampled household taps across a system; individual homes with lead service lines or fixtures can differ.
- It covers public water systems only. Private wells have no record here.
- Publication lag: the newest quarter may not be in this download yet.
How PurityMap uses it
From the file to 4,057 findings
- Step 1
Ingest the national file
SDWA_LCR_SAMPLES.csv from EPA’s SDWA download, collected 2026-07-09.
- Step 2
Keep the 90th-percentile results
Lead and copper 90th-percentile values per system and monitoring round, with the period dates.
- Step 3
Attach them to each system
Each system’s lead and copper findings cite the round they came from, with its dates.
- Step 4
4,057 findings depend on it
Each finding links back here, so you can trace a value to this record.
Update history
Next EPA release: quarterlyWhen this source last changed
SDWIS Lead & Copper Rule 90th-percentile results ingested.
How to interpret this source
A source is a public record, not a verdict.
Coverage, sampling location, reporting limits, and publication lag determine what any finding drawn from it can support.