City of Baltimore: what the federal PFAS data say

Baltimore, MD · serves about 1,600,000 people · source: surface water · PWSID MD0300002

In one line

No PFAS or lithium detection in the UCMR 5 samples read. Data: EPA UCMR 5, the national monitoring programme that ran 2023–2025 and was published as a final dataset in August 2026. Read 2026-10-31.

The numbers

Contaminant	Samples	Highest (ng/L)	2024 MCL (ng/L)	Last sample
PFOA	12	< 4	4	2025-05-13
PFOS	12	< 4	4	2025-05-13
PFHxS	12	< 3	10	2025-05-13
PFNA	12	< 4	10	2025-05-13
HFPO-DA	12	< 5	10	2025-05-13
PFBS	12	< 3	—	2025-05-13
lithium	12	< 9 µg/L	—	2025-05-13

ng/L = nanograms per litre (parts per trillion); lithium is shown in µg/L (micrograms per litre) as EPA reports it. "Highest" is the single highest sample at any entry point or tap in the UCMR 5 programme, not an average and not necessarily what reaches your home. "< MRL" means every sample was below the minimum reporting level, which is a laboratory limit, not a health limit.

What the limits mean

In April 2024 EPA set the first national limits for PFAS in drinking water: 4.0 ng/L for PFOA and PFOS, 10 ng/L for PFHxS, PFNA and HFPO-DA (GenX), plus a hazard index for mixtures. Utilities have until 2029 to comply. In May 2025 EPA announced it intends to keep the PFOA and PFOS limits, extend their deadline to 2031, and reconsider the other three. We show the 2024 numbers and mark the status as of our read date; check the EPA PFAS rule page for the current state.

A sample above an MCL in this table is a measurement, not a violation: compliance is judged on running annual averages after the deadline, not on single UCMR samples.

What you can do, in order

Read your utility's own report. Every community water system publishes a Consumer Confidence Report each year; it is the most local number you can get. EPA: find your CCR.
Ask about lead pipes. Since 16 October 2024 every system must have a lead service line inventory; ask whether your address is on it.
Test your own tap if you want certainty. Only a sample from your tap measures your water; see how to read a water report.
If PFAS are your concern, filters certified to NSF/ANSI 53 or 58 with a PFOA/PFOS reduction claim are the ones with a tested claim; our list: lead and PFAS certified filters. The yearly cost is on filter cost per year.

We do not give medical advice. If you are pregnant, formula-feeding an infant, or have a health condition, talk to your clinician about your water.

Sources

US EPA, UCMR 5 occurrence data, final dataset (August 2026): epa.gov/dwucmr. Read 2026-10-31.
US EPA, SDWIS via Envirofacts (population served, source water). Read 2026-10-31.
US EPA, PFAS National Primary Drinking Water Regulation, 40 CFR 141.61 (26 April 2024); EPA announcement of 14 May 2025 on compliance timeline and reconsideration.