Town of Poolesville water quality
Poolesville, MD · serves 6,005 people (2,105 connections) · Groundwater under influence of surface water · Local government · EPA ID MD0150002
Data: U.S. EPA · How we read the data · How we check it
Summary
PFAS above the 2024 federal limits. Systems have until 2029 to meet the PFAS limits.
Is it an emergency? No: PFAS limits are about years of exposure, not a glass of water, and nothing in EPA's data calls for you to stop drinking the water today. If your utility ever issues a boil-water or do-not-drink notice, follow it.
- PFAS
- Above limitPFOA, PFOS above the federal limit in EPA's 2023–2025 testing (PFOA 5.3 ppt vs a limit of 4 ppt, PFOS 6.05 ppt vs a limit of 4 ppt, where ppt = parts per trillion).
- Lithium
- Above screening levelHighest result 41.1 ppb. EPA uses 10 ppb to decide what to study further. It is not a health limit, and there is no federal limit for lithium. About 1 in 4 systems tested were above it.
- Lead
- Out of dateEPA's national database has no lead results for this system since 2018 (then 5 ppb, 90th percentile). Systems this size normally test every one to three years, so this most likely means newer results were not reported to EPA, not that testing stopped. Ask the utility for its latest results.
- Violations
- None health-basedNo health-based violations since 2016.
- Pregnant, or mixing baby formula with tap water? Babies drink more water for their size, so PFAS exposure matters more for them. Consider bottled water or a filter certified for PFAS for formula, and ask your doctor. Health effects.
- To lower your PFAS exposure now, a home filter certified for PFAS reduction works (reverse osmosis, or activated carbon certified to NSF/ANSI 53 or 58). Filters for these results.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read Town of Poolesville's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (240) 793-4866. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 9 entry points tested Feb 2023 to Nov 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Above limit Limit 4 ppt | 5.3 ppt 1.32× the limit |
| PFOS Above limit Limit 4 ppt | 6.05 ppt 1.51× the limit |
| PFHxS Detected, below limit Limit 10 ppt | 6.85 ppt 69% of the limit |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Detected, below limit Limit 1 | 0.69 |
| PFBS Detected, below limit Guideline 2,000 ppt | 4.5 ppt |
| PFBA Detected, below limit Guideline 6,000 ppt | 7 ppt |
| PFHxA Detected, below limit Guideline 3,000 ppt | 9.8 ppt |
| PFPeA Detected, no limit | 14.6 ppt |
| PFHpA Detected, no limit | 5.25 ppt |
For context: the PFOA average is higher than at 88% of the Maryland systems EPA tested and the PFOS average is higher than at 88% of the Maryland systems EPA tested.
29 PFAS tested, 8 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Detected in 19 of 19 samples. Highest result 41.1 ppb. EPA's non-enforceable screening level is 10 ppb. Above screening level The screening level is how EPA decides what to study further, not a health limit. There is no federal limit for lithium and no filter is certified to remove it. About lithium.
Lead and copper
Latest 90th percentile: 5 ppb lead (Jan 2016 – Dec 2018). No results since 2018
This is the newest lead result in EPA's national database. Utilities report lead results to their state, and states pass them to EPA. Gaps like this usually mean the newer results did not reach EPA's database, not that the utility stopped testing. Results this old may not reflect the water today. Ask the utility or your state drinking water program for the latest lead monitoring.
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2016 – Dec 2018 | 5 ppb |
| Jan 2013 – Dec 2015 | -5 ppb |
| Jan 2010 – Dec 2012 | 0 ppb |
Earlier results (9)
| Jan 2007 – Dec 2009 | 0 ppb |
| Jan 2004 – Dec 2006 | 6 ppb |
| Jan 2001 – Dec 2003 | 0 ppb |
| Jan 1998 – Dec 2000 | 0 ppb |
| Jan 1997 – Dec 1999 | 5 ppb |
| Jan 1995 – Dec 1995 | 0 ppb |
| Jan 1994 – Dec 1994 | 5 ppb |
| Jan 1993 – Jun 1993 | 0 ppb |
| Jul 1992 – Dec 1992 | 0 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Where it serves
Poolesville
ZIP codes the system reported serving: 20837
Nearby utilities
- City of Rockville Rockville · 14 mi
- City of Frederick Frederick · 20 mi
- New Design – Frederick County Water System Frederick · 20 mi
- Town of Mount Airy Mount Airy · 21 mi · PFAS above limit
- Town of Middletown Middletown · 22 mi · PFAS above limit
- Washington Suburban Sanitary Commission Laurel · 30 mi
Questions
Is Town of Poolesville water safe to drink?
Town of Poolesville has no health-based violations since 2016. EPA testing found PFAS above the 2024 federal limits, which systems must meet by 2029. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Town of Poolesville water have PFAS?
Yes. EPA's 2023–2025 testing of Town of Poolesville found 8 PFAS at least once. The highest entry-point averages were above the federal limit for PFOA and PFOS: PFOA 5.3 ppt, PFOS 6.05 ppt (limit 4 ppt for PFOA and PFOS, 10 ppt for the others).
What is the lead level in Town of Poolesville water?
The most recent 90th-percentile lead result for Town of Poolesville is 5 ppb, for the period ending Dec 2018, which is more than five years old. The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for MD0150002: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID MD0150002).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask Town of Poolesville at (240) 793-4866, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.