UCMR 5 PFAS Sampling: What the Records Actually Show
Key Takeaways
- 1
UCMR 5 requires utilities serving 3,300+ people to test for 29 PFAS compounds through 2025.
- 2
A UCMR 5 detection means a compound was measured above the minimum reporting level — it is a monitoring record, not a violation.
- 3
EPA uses UCMR 5 data to inform future rulemaking, not to trigger immediate compliance action.
- 4
Your utility's sampling records are public and searchable through EPA and Water Utility Report.
Since 2023, EPA's Unregulated Contaminant Monitoring Rule 5 (UCMR 5) has required thousands of water utilities to test for 29 PFAS compounds. The results are now appearing in public databases — but the records can be confusing. Here is what they actually mean.
What is UCMR 5?
UCMR 5 is EPA's fifth round of the Unregulated Contaminant Monitoring Rule, running from 2023 through 2025. It requires public water systems serving 3,300 or more people — plus a representative sample of smaller systems — to sample for 29 PFAS compounds and report results to EPA.
What a detection means in the records
Each UCMR 5 result lists whether a compound was detected above the Minimum Reporting Level (MRL). An MRL is the lowest concentration a lab can reliably measure. Detection means the compound was present above that threshold — it does not automatically mean a regulatory limit was exceeded.
UCMR 5 detections are monitoring records. Because PFAS Maximum Contaminant Levels (MCLs) were finalized in April 2024, a utility may have UCMR 5 detections on record while still being in a compliance grace period. Water Utility Report displays these as sampling records, not violations.
What this does not mean
- A UCMR 5 detection is not a violation of current drinking water standards.
- Water Utility Report does not determine whether any water supply is safe or unsafe to drink.
- These records reflect official testing data — they are not emergency alerts.
- UCMR 5 results do not tell you about treatment currently in place at your utility.
What to check next
- Search your utility's UCMR 5 sampling records on Water Utility Report.
- Review your utility's most recent Consumer Confidence Report for treatment and compliance context.
- Check EPA's UCMR 5 data dashboard for national context and compound-level summaries.
- If you have questions about a specific detection, contact your utility directly.
Frequently Asked Questions
Sources
Last updated: 2026-05-01 · Water Utility Report
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