Community Water System · PWS MD0150003
City of Rockville
Maryland - drinking water served from surface water sources to 52,000 people, tracked in EPA SDWIS and UCMR5.
- 52,000
- People served
- 220
- EPA violations
- 4
- Health-based
- 4 PFAS
- UCMR5 result
The verdict
EPA records 220 drinking-water violations at City of Rockville, 2% of them health-based - above the Maryland per-system average, and UCMR5 testing detected 4 PFAS compounds.
- 220
- Total EPA violations on record
- 2%
- Health-based (MCL / treatment failure)
- 52,000
- People served by this system
- 4
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: City of Rockville
City of Rockville is a local-owned community water system that delivers drinking water to 52,000 residents in Maryland (Montgomery County) through 17,500 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 220 total violations for this system , of which 4 (2%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 214 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.
The most frequently cited contaminant at this system is Lead and Copper Rule, recorded in 19 violations (MR). Under EPA's UCMR5 PFAS monitoring program, 4 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 6.5 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.
Across Maryland, EPA tracks 3,215 public water systems serving 6,070,211 people, with 60,496 cumulative violations and 18,132 health-based violations on record. About 80% of systems in the state carry at least one violation, and state-wide the average per system is 18.8 violations. Statewide, 50 of 83 UCMR5-tested systems have reported PFAS detections (60.2%).
City of Rockville's 220 violations sit above the Maryland average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
4 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 17,500
- County
- Montgomery
- School/Daycare
- No
- MCL Violations
- 4
- Monitoring Violations
- 214
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Lead and Copper Rule | MR | 19 | 2013 |
| Coliform (TCR) | MR | 7 | 2008 |
| Cadmium | MR | 7 | 2006 |
| Trichloroethylene | MR | 5 | 2008 |
| 1,2-Dichloroethane | MR | 4 | 2002 |
| 1,1,1-Trichloroethane | MR | 4 | 2002 |
| CHLOROBENZENE | MR | 4 | 2002 |
| Benzene | MR | 4 | 2002 |
| Toluene | MR | 4 | 2002 |
| Ethylbenzene | MR | 4 | 2002 |
| Barium | MR | 4 | 1999 |
| Chromium | MR | 4 | 1999 |
| Nickel | MR | 4 | 1999 |
| Xylenes, Total | MR | 4 | 2002 |
| Beryllium, Total | MR | 4 | 1999 |
| Thallium, Total | MR | 4 | 1999 |
| Selenium | MR | 4 | 1999 |
| 1,2,4-Trichlorobenzene | MR | 4 | 2002 |
| DICHLOROMETHANE | MR | 4 | 2002 |
| 1,1-Dichloroethylene | MR | 4 | 2002 |
| Carbon tetrachloride | MR | 4 | 2002 |
| 1,2-Dichloropropane | MR | 4 | 2002 |
| o-Dichlorobenzene | MR | 4 | 2002 |
| Tetrachloroethylene | MR | 4 | 2002 |
| p-Dichlorobenzene | MR | 4 | 2002 |
| TTHM | MCL | 4 | 2008 |
| Endrin | MR | 4 | 2023 |
| Methoxychlor | MR | 4 | 2023 |
| Di(2-ethylhexyl) adipate | MR | 4 | 2023 |
| Vinyl chloride | MR | 4 | 2002 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 7 of 116 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 6/7/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTA | 6/7/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 6/7/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMBA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 6/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 6/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 6/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 6/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 6/7/2023 | 3.80 ppt | 3.00 ppt | Detected |
| PFHxA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 6/7/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 6/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 6/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| HFPO-DA | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 3/8/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTA | 3/8/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| NEtFOSAA | 3/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 3/8/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFOS | 3/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 3/8/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFDA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 3/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFBS | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 3/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeS | 3/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFEESA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 3/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxA | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 3/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 3/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for City of Rockville.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID MD0150003 on SDWISSource: EPA SDWIS Federal Reports Search
Maryland Drinking Water Authority
Maryland's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.
Find MD regulator via EPA SDWISViolation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2025 | LEAD AND COPPER RULE REVISIONS | RPT | 1 | SDWIS / MD0150003 / 5200 |
| 2023 | Endrin | MR | 4 | SDWIS / MD0150003 / 2005 |
| 2023 | Methoxychlor | MR | 4 | SDWIS / MD0150003 / 2015 |
| 2023 | Di(2-ethylhexyl) adipate | MR | 4 | SDWIS / MD0150003 / 2035 |
| 2023 | Simazine | MR | 4 | SDWIS / MD0150003 / 2037 |
| 2023 | Di(2-ethylhexyl) phthalate | MR | 4 | SDWIS / MD0150003 / 2039 |
| 2023 | Hexachlorocyclopentadiene | MR | 4 | SDWIS / MD0150003 / 2042 |
| 2023 | Atrazine | MR | 4 | SDWIS / MD0150003 / 2050 |
| 2023 | LASSO | MR | 4 | SDWIS / MD0150003 / 2051 |
| 2023 | HEXACHLOROBENZENE | MR | 4 | SDWIS / MD0150003 / 2274 |
| 2023 | Benzo(a)pyrene | MR | 4 | SDWIS / MD0150003 / 2306 |
| 2023 | Chlordane | MR | 4 | SDWIS / MD0150003 / 2959 |
| 2023 | BHC-GAMMA | MR | 4 | SDWIS / MD0150003 / 2010 |
| 2023 | Heptachlor epoxide | MR | 4 | SDWIS / MD0150003 / 2067 |
| 2023 | Toxaphene | MR | 4 | SDWIS / MD0150003 / 2020 |
How City of Rockville Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | City of Rockville | Maryland avg | Federal benchmark |
|---|---|---|---|
| Total violations | 220 | 18.8 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 4 | 5.6 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | 4 compounds | 60.2% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 52,000 | 1,888 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 3,215 regulated public water systems in Maryland.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is City of Rockville water safe to drink? ▼
How many people does City of Rockville serve? ▼
What type of violations does City of Rockville have? ▼
Has PFAS been detected in City of Rockville water? ▼
What water source does City of Rockville use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.