City of Rockville water quality
Rockville, MD · serves 52,000 people (17,500 connections) · Surface water · Local government · EPA ID MD0150003
Data: U.S. EPA · How we read the data · How we check it
Buys water from Washington Suburban Sanitary Commission. Treated water bought from another system can carry that system's contaminants.
Summary
No limits exceeded in the data EPA has, but the record is incomplete: no lead results since 2018.
- PFAS
- Detected, below limit4 of 29 PFAS found at least once. All averages below the federal limits.
- Lead
- Out of dateEPA's national database has no lead results for this system since 2018 (then 0 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.
- 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 City of Rockville'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. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 1 entry point tested Mar 2023 to Dec 2023. "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 Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| 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 | 0.00045 |
| PFBS Detected, below limit Guideline 2,000 ppt | 0.9 ppt |
| PFBA Detected, below limit Guideline 6,000 ppt | 1.3 ppt |
| PFHxA Detected, below limit Guideline 3,000 ppt | 2.82 ppt |
| PFPeA Detected, no limit | 4.1 ppt |
29 PFAS tested, 4 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
Not detected in 4 samples (reporting limit 9 ppb). About lithium.
Lead and copper
Latest 90th percentile: 0 ppb lead (Jan 2018 – Jun 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 2018 – Jun 2018 | 0 ppb |
| Jul 2017 – Dec 2017 | -2 ppb |
| Jan 2017 – Dec 2017 | -2 ppb |
Earlier results (9)
| Jan 2014 – Dec 2016 | -5 ppb |
| Jan 2011 – Dec 2013 | 0 ppb |
| Jan 2008 – Dec 2010 | 3 ppb |
| Jan 2005 – Dec 2007 | 3 ppb |
| Jan 2002 – Dec 2002 | 2 ppb |
| Jan 1999 – Dec 2001 | 2 ppb |
| Jan 1996 – Dec 1996 | 6 ppb |
| Jan 1995 – Dec 1995 | 0 ppb |
| Jan 1994 – Dec 1994 | 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.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 10.8 ppb | 300 ppb |
| 1,4-Dioxane | 0.071 ppb | 0.35 ppb |
| Chromium-6 | 0.13 ppb | – |
| Strontium | 0.25 ppm | 1.5 ppm |
| Chlorate | 87.7 ppb | 210 ppb |
| Molybdenum | 1.2 ppb | 40 ppb |
| Vanadium | 0.66 ppb | 21 ppb |
Where it serves
ZIP codes the system reported serving: 20850, 20851, 20852, 20854
Nearby utilities
- Town of Poolesville Poolesville · 14 mi · PFAS above limit
- Washington Suburban Sanitary Commission Laurel · 16 mi
- Howard County Dept. of Public Works Distribution Columbia · 18 mi
- Town of Mount Airy Mount Airy · 20 mi · PFAS above limit
- Fort George G. Meade Water System Fort Meade · 22 mi
- Crofton-Odenton Water System Odenton · 25 mi
Questions
Is City of Rockville water safe to drink?
City of Rockville has no health-based violations since 2016. EPA testing found no PFAS above the federal limits. 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 City of Rockville water have PFAS?
Yes. EPA's 2023–2025 testing of City of Rockville found 4 PFAS at least once. None of the averages were above the federal limits.
What is the lead level in City of Rockville water?
The most recent 90th-percentile lead result for City of Rockville is 0 ppb, for the period ending Jun 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 MD0150003: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID MD0150003).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask City of Rockville, 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.