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Tap water quality report

ZIP 06831 — Darien, CT

EPA monitoring across the 2 water suppliers serving ZIP 06831 in Darien, CT detected 23 contaminants. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier below, with the EPA limit for each.

2
water suppliers
172,511
people served
23
contaminants found

What was found in ZIP 06831

The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
2372.5 µg/L 24%
of the EPA limit 10000 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
Nitrate-Nitrite
1723.2 µg/L 17%
of the EPA limit 10000 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
Fluoride
858.5 µg/L 21%
of the EPA limit 4000 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 895 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Chlorite
631.5 µg/L 63%
of the EPA limit 1000 µg/L
Highest in the ZIP: AQUARION-GREENWICH · 53,297 people · 2019
1/2 SYR4
Copper
352.5 µg/L 27%
of the EPA limit 1300 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 407.5 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
TTHM
78.35 µg/L 98%
of the EPA limit 80 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 84.25 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Chloroform
58.75 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 66 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
49.35 µg/L 82%
of the EPA limit 60 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 61.25 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Barium
26.55 µg/L 1.3%
of the EPA limit 2000 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 46.45 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Trichloroacetic Acid
30 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 31 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Dichloroacetic Acid
21.4 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 29 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Bromodichloromethane
17 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 19 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Lead
18.6 µg/L 124%
of the EPA limit, at the 95th percentile of samples — 15 µg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
Dibromochloromethane
4 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
Monochloroacetic Acid
2 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
Highest in the ZIP: 3 µg/L — AQUARION-GREENWICH · 53,297 people · 2019
2/2 SYR4
Bromoform
1 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
1/2 SYR4
Dibromoacetic Acid
1 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
Monobromoacetic Acid
1 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2019
2/2 SYR4
PFOA
0.0043 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2025
Highest in the ZIP: 0.0056 µg/L — AQUARION-GREENWICH · 53,297 people · 2025
2/2 UCMR-5
PFOS
0.0041 µg/L
No EPA limit set
Highest in the ZIP: AQUARION-GREENWICH · 53,297 people · 2025
1/2 UCMR-5
Pfhxa
0.0030 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2025
Highest in the ZIP: 0.0040 µg/L — AQUARION-GREENWICH · 53,297 people · 2025
2/2 UCMR-5
Pfpea
0.0031 µg/L
No EPA limit set
Main supplier: AQUARION-STAMFORD · 119,214 people · 2025
Highest in the ZIP: 0.0038 µg/L — AQUARION-GREENWICH · 53,297 people · 2025
2/2 UCMR-5
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: AQUARION-STAMFORD · 119,214 people · 2026
2/2 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 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.

Water suppliers serving ZIP 06831

SupplierStatePopulation served
AQUARION-STAMFORD CT 119,214
AQUARION-GREENWICH CT 53,297

Frequently asked questions about ZIP 06831 tap water

Is the tap water in ZIP 06831 safe to drink?

EPA testing detected 23 contaminants across the water suppliers serving ZIP 06831. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.

Which water suppliers serve ZIP 06831?

2 public water suppliers report EPA drinking-water monitoring for ZIP 06831. Each is listed above with its population served.

What contaminants are in ZIP 06831's water?

EPA monitoring detected Nitrate, Nitrate-Nitrite, Fluoride, Chlorite, Copper, and others across this ZIP's suppliers. The full list with levels and sources is above.