Every year, by July 1, every Connecticut water utility sends out a Consumer Confidence Report. It tells you what was found in your water the previous year and how those results compare to federal and state standards.
Most people throw it away. The ones who read it usually walk away either falsely reassured or needlessly alarmed, because the thing is written in regulatory language that needs translating.
Here's the translation.
What the Report Actually Contains
The CCR lists the contaminants detected during testing, meaning the chemicals, metals, and microorganisms found in the water system. For each one you get:
- The highest level detected (or the range of detected levels)
- The EPA's Maximum Contaminant Level (MCL), which is the legal limit
- The MCL Goal (MCLG), the level at which no known health risk exists (often zero for carcinogens)
- The likely source of the contaminant
The report covers what the EPA requires utilities to test for. It says nothing about the contaminants the EPA doesn't require testing for, and there are many of those.
What Does "ND" Mean on Your Water Report?
"ND" in a CCR means "not detected." It does not mean "not present."
Every test has a detection limit, a minimum concentration below which the test simply can't identify the contaminant reliably. If something is present below that floor, the test returns "ND." The contaminant may still be in your water.
This matters most for PFAS. The EPA's new PFAS limits are set at 4-10 parts per trillion, which are extraordinarily low concentrations. Plenty of older PFAS tests had detection limits higher than the new MCLs. So a CCR from 2022 saying "PFAS: ND" may have been using a test that couldn't see PFAS at the levels now considered unsafe. If you live in Fairfield County, that's worth knowing, because Aquarion's PFAS compliance deadline is 2029, not 2031: the 2031 date is a proposed extension systems would have to request.
The MCL vs. MCLG Gap
For many contaminants, the MCL (the legal limit) and the MCLG (the health-based goal) are different numbers. Sometimes very different.
For lead, the MCLG is zero. There is no safe level of lead in drinking water. The MCL, the legal limit that triggers regulatory action, is 15 parts per billion (measured as a 90th percentile of samples). So a system can run up to 14.9 ppb in 90% of its samples, sit in full compliance with the law, and still be nowhere near the health-based goal of zero.
For trihalomethanes (disinfection byproducts), the MCLG for chloroform is zero (it's a probable carcinogen). The MCL is 80 ppb. A CCR that says your THM level is 60 ppb and "meets MCL" is telling you the legal limit is satisfied. It is not telling you the health-based goal is met.
When you read a CCR, look at the MCLG column, not just the MCL column. The MCLG tells you what the EPA considers truly safe. The MCL tells you what's legally required.
What the Report Doesn't Tell You
Your household level. The CCR reports system averages and the highest detected level across the system. Your tap may be higher or lower than the system average, depending on your home's plumbing, your proximity to the water main, and your service line material.
Private well data. If you're on a private well, there is no CCR for your water. You are responsible for your own testing.
Unregulated contaminants. PFAS wasn't regulated until 2024. Before that it didn't show up in CCRs even when it was in the water. Other contaminants are in the same position today, some newly emerging, some just not yet regulated. They may be in your water and they won't appear in any CCR.
What happened last week. The CCR covers the previous calendar year. A contamination event that happened after the reporting period won't appear until next year's report.
How to Use the Report Effectively
Read the MCLG column, not just the MCL column. If the MCLG is zero and the detected level is above zero, you have a contaminant present that the EPA considers to have no safe level.
Look for footnotes. CCRs often include footnotes explaining why certain results are listed as "meets MCL" despite being above zero. These footnotes sometimes contain important context.
Use the report as a starting point, not an endpoint. The CCR tells you what the utility found in its system-wide testing. It doesn't tell you what's coming out of your specific tap. If the CCR shows any detected lead, any detected PFAS, or any detected disinfection byproducts, consider household-level testing or filtration. For a town-by-town breakdown of what to look for, see our Connecticut water quality guide.
Want ZIP-level context before deciding whether to test? Enter your ZIP code at CheckYourTap.com to see available public-system or regional monitoring records associated with the ZIP. This is not a test of a tap, well, or property. Free, in 30 seconds.
And if you're on a private well, the CCR is irrelevant to you. Test your own water.
Keep Reading
- A Practical Guide to Water Quality in Connecticut's Major Towns: What's Actually in the Water Where You Live
- Boiling Your Water Removes Some Things and Concentrates Others. Know the Difference Before You Boil.
- The Water Test Your Bank Required Doesn't Test for What's Actually Dangerous
Sources: EPA Consumer Confidence Report Rule; CT DPH CCR Guidance; EPA Drinking Water Standards and Health Advisories; NSF International Water Testing Guide; checkyourtap.com Water Quality Data.
