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City water profile

Colchester water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Colchester, Connecticut.

Median indexed hardness

71PPM

One indexed ZIP

Range 70.5–70.5 PPM

State comparison
18 PPM above
State hardness rank
#23 of 52
Matched utilities
8
Active health records
2

City summary

What the indexed records say

Colchester has 1 published ZIP profile across New London County. The indexed median is 71 PPM, compared with 53 PPM across Connecticut.

Among the 52 Connecticutcities with an indexed median, Colchester ranks #23from highest to lowest. Across all 98 state ZIP profiles, available estimates run from 42.8to 114 PPM.

Because only one ZIP is represented, the city median and range are the same local estimate. It should not be read as multiple independent samples across the community.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard1 ZIP
Hard0 ZIPs
Very hard0 ZIPs

1 of 1 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
11.9 miles
Profiles with evidence
1/1

Confidence labels

High: 0Moderate: 1Low: 0

Observation window: May 11, 2016 to Dec 2, 2025.

ZIP directory

Water reports in Colchester

Open a ZIP for site-level provenance and measurements.

ZIP code

06415

Moderately Hard

70.5 PPM

Nearest site
11.9 mi
Confidence
Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Colchester Sewer & Water Commission

PWSID CT0280011

Groundwater
System population served
4,020
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Ctwc - Amston Lake Division

PWSID CT0670331

Groundwater
System population served
910
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Colchester Estates

PWSID CT0280041

Groundwater
System population served
276
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Ctwc - Westchester Village

PWSID CT0282001

Groundwater
System population served
252
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Westchester Hills Condominium Assn.

PWSID CT0280031

Groundwater
System population served
225
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Colchester Commons

PWSID CT0286011

Groundwater
System population served
224
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Knob Hill Condominiums

PWSID CT0280051

Groundwater
System population served
84
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Ctwc - Ponemah Village

PWSID CT0280071

Groundwater
System population served
60
Last reported
Jun 29, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

2 unique active health-based records appear among associated systems. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
E. COLICT0280011Mar 1, 2026Archived
Consumer Confidence RuleCT0280011Aug 10, 2025Resolved
Consumer Confidence RuleCT0280011Jul 1, 2025Resolved
Public NoticeCT0280011Jun 15, 2025Resolved
Public NoticeCT0280011Jun 15, 2025Resolved
Lead and Copper RuleCT0280041Dec 30, 2024Resolved
Lead and Copper RuleCT0286011Dec 30, 2024Resolved
LEAD AND COPPER RULE REVISIONSCT0280041Oct 17, 2024Unaddressed · health-based
LEAD AND COPPER RULE REVISIONSCT0280041Oct 17, 2024Unaddressed
LEAD AND COPPER RULE REVISIONSCT0286011Oct 17, 2024Unaddressed

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Colchester

Is the water hard?

The indexed city median is 71 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.