Methodology
Dataset and scope
TapScore processes EPA ECHO's 2026 Q2 SDWA download, published July 9, 2026. It includes active Community Water Systems. Private wells and non-community systems are outside this directory.
The EPA violations/enforcement table can repeat the same violation for multiple enforcement actions. We deduplicate on EPA violation ID before calculating counts.
Five-year window
“Recent” means a compliance-period start date from July 1, 2021 through June 30, 2026. Historical totals can include older records. “Open” means EPA's row is not marked resolved in this snapshot.
TapScore compliance-history grade
The letter is a deterministic TapScore summary, not an EPA grade and not a water-safety determination. It uses only recent record count and recent records EPA marks health-based.
Grade A — No recent records
No EPA violation records in the five-year window.
Grade B — Few non-health records
One or two recent records and none marked health-based.
Grade C — Some recent records
No recent health-based records, or no more than one health-based record among no more than five recent records.
Grade D — Several health-based records
Between two and five recent health-based records.
Grade F — Frequent health-based records
More than five recent health-based records.
Publication controls
High-information pages are released progressively. URLs scheduled for a future date or excluded as low-value are not linked, return not found when requested directly, and do not enter the sitemap. This reduces duplicate and thin indexable pages.
Limitations
- Compliance records are not current concentration measurements.
- Records can be historical, resolved, delayed, corrected, or incomplete.
- Service-area ZIP and city associations do not prove which utility serves a specific address.
- Combined service populations can overlap and must not be read as unique resident counts.
- Reference pages summarize standards; EPA's current rule text controls.