Drinking water quality · 2024
What's in Rockville, MD tap water
18 contaminants were measured in the Rockville, MD water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 18
- Over federal limit
- 0
- Approaching the limit
- 1
- Service area
- MD
PFAS — EPA UCMR5 (2023–2025)
4 PFAS compounds detected in Rockville, MD
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFBS
● Detected (no federal limit)PFPeA
● Detected (no federal limit)PFHxA
● Detected (no federal limit)PFBA
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Rockville, MD's drinking water comes from surface water, drawn from 1 source.
Source
- POTOMAC RIVER
Treatment
- POTOMAC FILTER PLANT
Distribution
Also buys water from WASHINGTON SUBURBAN SANITARY COMMISSION.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based1 violation on record · most recent Oct 2008resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 69 ug/LRunning annual avgSystem-wide | None set | Approaching the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 24 ug/LRunning annual avgSystem-wide | None set | Within the limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. | 2.07 ng/LAverageSystem-wide | 4 ng/LMCL | Within the limit |
| PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. | 2 ng/LAverageSystem-wide | 4 ng/LMCL | Within the limit |
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 1.13 ng/LAverageSystem-wide | 10 ng/LMCL | Within the limit |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | 0.27 ng/LAverageSystem-wide | 10 ng/LMCL | Within the limit |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | 0 ng/LAverageSystem-wide | 10 ng/LMCL | None detected |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 1.32 mg/LReported levelSystem-wide | 4 mg/LMCLG | Within the limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Chlorine Free | 1.32 mg/LMaximumSystem-wide | 4 mg/LMCLG | Within the limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.26 NTUMaximumSystem-wide | None set | Within the limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.64 mg/LMaximumSystem-wide | 4 mg/LMCLG | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 1.3 mg/LMinimumSystem-wide | 10 mg/LMCLG | Within the limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 0.1 mg/L90th percentileAt the tap | 1.3 mg/LMCLG | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 0.037 mg/LMaximumLevel Detected Or Average | 2 mg/LMCLG | Within the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected ug/L90th percentileAt the tap | 0 ug/LMCLG | Within the limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AtrazineA widely used agricultural herbicide that reaches water through runoff. | Not detected ug/LMaximumLevel Detected Or Average | None set | None detected |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Escherichia coli (E. coli)Escherichia coli — bacteria found in the gut of humans and animals. | 3Reported levelSystem-wide | 0MCLG | Detected — no federal limit |
People also ask about Rockville, MD's water
+Is Rockville, MD tap water safe to drink in 2024?
Every one of the 18 contaminants measured in Rockville, MD's 2024 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in Rockville, MD tap water?
18 contaminants were measured in Rockville, MD's 2024 Consumer Confidence Report, spanning pfas ("forever chemicals"), metals, and disinfection byproducts. 13 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Are any contaminants in Rockville, MD tap water approaching the federal limit?
One contaminant is between 80% and 100% of the federal limit in this report: TTHM. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from Rockville, MD's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Rockville, MD's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.