Is City of Rockville Tap Water Safe? Quality Report

Water source: Surface water
Ownership: Local government
Counties served: Montgomery

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

219

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Resolved	2008-10-01 → 2008-12-31
MCL	Health-based	Resolved	2008-10-01 → 2008-12-31
MCL	Health-based	Resolved	2008-10-01 → 2008-12-31
MCL	Health-based	Resolved	2008-10-01 → 2008-12-31
RPT	Monitoring	Resolved	2025-07-02
MR	Monitoring	Resolved	2023-07-01 → 2023-09-30
MR	Monitoring	Resolved	2023-07-01 → 2023-09-30
MR	Monitoring	Resolved	2023-07-01 → 2023-09-30
MR	Monitoring	Resolved	2023-07-01 → 2023-09-30
MR	Monitoring	Resolved	2023-07-01 → 2023-09-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).

Contaminant	Max	Detection rate	Period
Pfpea	0.0065 µg/L	3/4	2023
Pfhxa	0.0058 µg/L	2/4	2023
Pfba	0.0052 µg/L	1/4	2023
PFBS	0.0036 µg/L	1/4	2023

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
Total Haloacetic Acids (HAA5)	47.68 µg/L 79% of the EPA limit 60 µg/L worst single sample: 62.6 µg/L	162/162	SYR4	2012–2019
TTHM	95.1 µg/L 119% of the EPA limit, at the 95th percentile of samples — 80 µg/L worst single sample: 131 µg/L	161/162	SYR4	2012–2019
Chloroform	60.135 µg/L No EPA limit set worst single sample: 79.7 µg/L	68/69	SYR4	2012–2019
Bromodichloromethane	26.83 µg/L No EPA limit set worst single sample: 31 µg/L	67/68	SYR4	2012–2019
Dibromochloromethane	15.16 µg/L No EPA limit set worst single sample: 17.5 µg/L	63/66	SYR4	2012–2019
Dichloroacetic Acid	22.21 µg/L No EPA limit set worst single sample: 26.5 µg/L	59/59	SYR4	2012–2015
Trichloroacetic Acid	17.8 µg/L No EPA limit set worst single sample: 21.3 µg/L	59/59	SYR4	2012–2015
Dibromoacetic Acid	3.51 µg/L No EPA limit set worst single sample: 3.8 µg/L	39/57	SYR4	2012–2015
Bromoform	2.28 µg/L No EPA limit set worst single sample: 2.5 µg/L	12/68	SYR4	2012–2019
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L	12/12	LCR	2018
Nitrate	1800 µg/L 18% of the EPA limit 10000 µg/L	12/12	SYR4	2012–2018
Monochloroacetic Acid	4.72 µg/L No EPA limit set worst single sample: 5 µg/L	9/59	SYR4	2012–2015
Fluoride	688.5 µg/L 17% of the EPA limit 4000 µg/L worst single sample: 720 µg/L	8/8	SYR4	2012–2018
Barium	264.9 µg/L 13% of the EPA limit 2000 µg/L worst single sample: 360 µg/L	7/8	SYR4	2012–2018
Atrazine	0.2102 µg/L 7% of the EPA limit 3 µg/L worst single sample: 0.2200 µg/L	2/11	SYR4	2012–2018
Chromium	2.78 µg/L 2.8% of the EPA limit 100 µg/L worst single sample: 2.8 µg/L	2/8	SYR4	2012–2018
Di(2-ethylhexyl) Phthalate	2.4 µg/L 40% of the EPA limit 6 µg/L	1/11	SYR4	2012–2018
Nitrate-Nitrite	2040 µg/L 20% of the EPA limit 10000 µg/L	1/1	SYR4	2018

86 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalArsenicBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateGross Alpha, Excl. Radon And UGross Beta Particle ActivityHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidNetfosaaNfdhaNmefosaaOxamylPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Frequently asked questions about City of Rockville

Is City of Rockville tap water safe to drink?

EPA monitoring detected 22 contaminants in City of Rockville's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in City of Rockville's water?

EPA monitoring detected Total Haloacetic Acids (HAA5), TTHM, Chloroform, Bromodichloromethane, Dibromochloromethane, and others. The full list with the level and data source for each is above.

How many people does City of Rockville serve?

City of Rockville reports serving 52,000 people, per its EPA record.

Has City of Rockville had any water quality violations?

The EPA has 219 violations on file for City of Rockville, of which 4 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.