Is Mchenry Tap Water Safe? Quality Report

Water source: Ground water
Ownership: Local government
Counties served: McHenry

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

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Archived	1996-08-01 → 1996-08-31
MCL	Health-based	Archived	1996-08-01 → 1996-08-31
TT	Health-based	Resolved	1992-04-02
TT	Health-based	Resolved	1992-04-02
MR	Monitoring	Resolved	2025-07-01
MR	Monitoring	Resolved	2025-07-01
MR	Monitoring	Resolved	2025-07-01
MR	Monitoring	Resolved	2023-10-01
MR	Monitoring	Resolved	2023-10-01
MR	Monitoring	Resolved	2023-10-01

PFAS detected

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

Contaminant	Max	Detection rate	Period
PFBS	0.0039 µg/L	1/8	2024

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
Copper	1760 µg/L 135% of the EPA limit, at the 95th percentile of samples — 1300 µg/L worst single sample: 2160 µg/L	48/60	SYR4	2014–2017
Lead	36 µg/L 240% of the EPA limit, at the 95th percentile of samples — 15 µg/L worst single sample: 100 µg/L	33/60	SYR4	2014–2017
Bromodichloromethane	12.78 µg/L No EPA limit set worst single sample: 13.6 µg/L	32/32	SYR4	2012–2019
Chloroform	12.39 µg/L No EPA limit set worst single sample: 14.4 µg/L	32/32	SYR4	2012–2019
Dibromochloromethane	12.1015 µg/L No EPA limit set worst single sample: 14.5 µg/L	32/32	SYR4	2012–2019
TTHM	40.63 µg/L 51% of the EPA limit 80 µg/L worst single sample: 42 µg/L	32/32	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	11.771 µg/L 20% of the EPA limit 60 µg/L worst single sample: 15.3 µg/L	28/32	SYR4	2012–2019
Dibromoacetic Acid	2.855 µg/L No EPA limit set worst single sample: 3.2 µg/L	24/32	SYR4	2012–2019
Bromoform	4.0422 µg/L No EPA limit set worst single sample: 4.49 µg/L	23/32	SYR4	2012–2019
Lead	0.0041 mg/L 27% of the EPA limit 0.0150 mg/L	22/22	LCR	2026
Trichloroacetic Acid	8.096 µg/L No EPA limit set worst single sample: 8.21 µg/L	20/32	SYR4	2012–2019
Barium	150 µg/L 7.5% of the EPA limit 2000 µg/L	17/17	SYR4	2012–2018
Fluoride	1214 µg/L 30% of the EPA limit 4000 µg/L worst single sample: 1270 µg/L	17/17	SYR4	2012–2018
Nitrate	640 µg/L 6.4% of the EPA limit 10000 µg/L	10/76	SYR4	2012–2019
Dichloroacetic Acid	5.376 µg/L No EPA limit set worst single sample: 5.4 µg/L	7/32	SYR4	2012–2019
Combined Radium (-226 And -228)	1.2497 pCi/L 25% of the EPA limit 5 pCi/L worst single sample: 1.313 pCi/L	4/9	SYR4	2012–2018
Nitrate-Nitrite	629.5 µg/L 6.3% of the EPA limit 10000 µg/L worst single sample: 640 µg/L	4/16	SYR4	2012–2018
Arsenic	1.58 µg/L 16% of the EPA limit 10 µg/L worst single sample: 1.6 µg/L	3/17	SYR4	2012–2018
Chromium	5.2 µg/L 5.2% of the EPA limit 100 µg/L	1/17	SYR4	2012–2018
Lithium	9.09 µg/L No EPA limit set	1/8	UCMR-5	2023

88 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: MCMAHON, JASON
Phone: 847-417-0565
Email: [email protected]

Frequently asked questions about Mchenry

Is Mchenry tap water safe to drink?

EPA monitoring detected 21 contaminants in Mchenry'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 Mchenry's water?

EPA monitoring detected Copper, Lead, Bromodichloromethane, Chloroform, Dibromochloromethane, and others. The full list with the level and data source for each is above.

How many people does Mchenry serve?

Mchenry reports serving 22,335 people in Illinois, per its EPA record.

Has Mchenry had any water quality violations?

The EPA has 98 violations on file for Mchenry, 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.