Is Norwalk, CT Tap Water Safe? Quality & Contaminants

What was found in Norwalk's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate	2830 µg/L 28% of the EPA limit 10000 µg/L	4/4	SYR4
Nitrate-Nitrite	2830 µg/L 28% of the EPA limit 10000 µg/L	4/4	SYR4
Fluoride	1080 µg/L 27% of the EPA limit 4000 µg/L	4/4	SYR4
Copper	1060 µg/L 82% of the EPA limit 1300 µg/L	4/4	SYR4
Lead	668 µg/L 4453% of the EPA limit, in the worst sample — 15 µg/L	4/4	SYR4
TTHM	109 µg/L 136% of the EPA limit, in the worst sample — 80 µg/L	4/4	SYR4
Chloroform	92.4 µg/L No EPA limit set	4/4	SYR4
Total Haloacetic Acids (HAA5)	75 µg/L 125% of the EPA limit, in the worst sample — 60 µg/L	4/4	SYR4
Barium	55 µg/L 2.8% of the EPA limit 2000 µg/L	4/4	SYR4
Trichloroacetic Acid	40 µg/L No EPA limit set	3/4	SYR4
Dichloroacetic Acid	36 µg/L No EPA limit set	3/4	SYR4
Bromodichloromethane	19 µg/L No EPA limit set	4/4	SYR4
Dibromoacetic Acid	13.7 µg/L No EPA limit set	3/4	SYR4
Dibromochloromethane	11.4 µg/L No EPA limit set	4/4	SYR4
Gross Beta Particle Activity	4.4 pCi/L No EPA limit set	1/4	SYR4
Bromoform	4 µg/L No EPA limit set	3/4	SYR4
Monochloroacetic Acid	3 µg/L No EPA limit set	3/4	SYR4
Di(2-ethylhexyl) Phthalate	1.52 µg/L 25% of the EPA limit 6 µg/L	1/4	SYR4
Monobromoacetic Acid	1 µg/L No EPA limit set	2/4	SYR4
cis-1,2-Dichloroethylene	0.7000 µg/L 1% of the EPA limit 70 µg/L	1/4	SYR4
PFOS	0.0112 µg/L No EPA limit set	2/4	UCMR-5
PFOA	0.0109 µg/L No EPA limit set	3/4	UCMR-5
Pfba	0.0076 µg/L No EPA limit set	2/4	UCMR-5
Pfhxa	0.0074 µg/L No EPA limit set	3/4	UCMR-5
Pfpea	0.0067 µg/L No EPA limit set	3/4	UCMR-5
PFBS	0.0064 µg/L No EPA limit set	2/4	UCMR-5
PFHXS	0.0042 µg/L No EPA limit set	1/4	UCMR-5
Pfhpa	0.0039 µg/L No EPA limit set	1/4	UCMR-5
Lead	0.0030 mg/L 20% of the EPA limit 0.0150 mg/L	4/4	LCR

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 single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Norwalk

Supplier	Population served
AQUARION-EASTERN FAIRFIELD COUNTY	351,756
SOUTH NORWALK ELECTRIC & WATER	42,000
NORWALK FIRST TAXING DISTRICT	40,256
AQUARION-DARIEN	18,737

Frequently asked questions about Norwalk tap water

Is Norwalk tap water safe to drink?

EPA testing detected 29 contaminants in the water serving Norwalk. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Norwalk?

4 public water suppliers report drinking-water monitoring for Norwalk, Connecticut to the EPA. Each is listed above with its population served.

What contaminants are in Norwalk's water?

The contaminants EPA monitoring detected in Norwalk include Nitrate, Nitrate-Nitrite, Fluoride, Copper, Lead. The full list, with the highest level found and the data source, is in the table above.

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.