How to read your water quality report

Every community water system, the kind that serves people where they live all year, has to give its customers a water quality report once a year. Its official name is the Consumer Confidence Report, or CCR. It covers what was found in the water during the previous calendar year, how that compares with the legal limits, and any violations.

Look for it on your utility’s website, in the mail, or in a notice with your water bill, or search your utility’s name plus “water quality report.” If you rent and don’t get a water bill, the utility still has to make a good-faith effort to reach you, and it has to give a copy to anyone who asks.

If your water comes from a private well, there’s no report: the rule covers community water systems only, and nobody tests a private well unless the owner does.

Reports look different from city to city, and states can change the format, but the same information has to be there. Here’s a sample built to the federal rule. The utility and its numbers are invented; the units, limits, typical sources, and required wording are real.

The table of detected contaminants is the heart of the report. Only contaminants that were actually detected appear in it, so a short table is a good sign. Read each row in this order:

1. Units. ppm, ppb, and ppt are a thousand times apart. The limit and the result are always in the same units.
2. Highest level against the MCL. This is the comparison that decides compliance. For contaminants judged on a running average, the highest level is the worst average, not the worst sample.
3. The MCLG. The health goal. When it’s zero, any detection is above it.
4. The range. How much results varied through the year or across the system.
5. The violation column. Any “Yes” must come with an explanation of how long it lasted, the health effects, and what was done.

The two definitions every report has to print explain the gap between the goal and the limit:

Have your report open? Pick a contaminant from its table and type the highest level. You’ll see where it sits between the health goal and the legal limit, and what that position means under the rule.

Lead is different from almost everything else in the report. It’s measured at taps inside homes, not at the treatment plant, because it mostly comes from the pipes on the way to you. The report gives three numbers: the 90th percentile of the homes tested, how many were above the action level, and the range.

Those homes aren’t your home. A low 90th percentile is good news about the system, but it can’t tell you what’s in your plumbing. Every report’s lead statement says where lead comes from:

From November 1, 2027, the required statement goes further and says plainly that one clean test doesn’t settle it:

Both versions list steps that help: flush your pipes before drinking water that’s been sitting, and use a filter certified to reduce lead. The newer one adds: use only cold water for drinking, cooking, and baby formula, and know that boiling doesn’t remove lead.

Utilities have had to inventory their service lines. By November 1, 2027, the report must also tell you how to see that inventory (with a direct link if it’s online), where to find complete lead tap results, what the utility does to control corrosion, and that schools and child care facilities can ask to have their water tested. You can also check your own service line with a key and a magnet: see how in From Cloud to Tap.

EPA rewrote the report rule in 2024, and the lead rule the same year. The changes reach your mailbox in stages, set out in the rule itself:

1. Find this year’s report and read the summary and the violations first.
2. Check each row of the table against its MCL, using the checker above if it helps.
3. Read the lead section, then check your own service line and plumbing if your home was built before 1986.
4. If PFAS are listed, look your system up in EPA’s UCMR 5 Data Finder. Forever Chemicals covers what the results mean.
5. Thinking about a filter? Match it to what’s actually in your water, and check what it’s certified to remove.
6. Questions? Call the number in the report. The report also lists when the utility’s board meets, and those meetings are where decisions about your water get made.