How to read the water quality report your utility sends you

What it is, and when it arrives

It is called a Consumer Confidence Report, and the EPA requires community water systems to deliver one to their customers every year by 1 July. If you rent, it may go to the landlord. If you never see one, you can look yours up directly through the EPA's tool or call the utility.

EPA, CCR information for consumers, page updated 21 November 2025. Lookup tool: sdwis.epa.gov/fylccr. Safe Drinking Water Hotline: 1-800-426-4791.

The four things the report must contain

1. The source. The lake, river or aquifer your water comes from. This one sentence tells you more about your risks than the rest of the document.
2. A summary of the risk of contamination of that source.
3. The regulated contaminants found in your water, with the levels detected.
4. The health effects of anything detected in violation of an EPA standard, plus required educational language about Cryptosporidium, nitrate, arsenic or lead when those apply.

EPA, CCR information for consumers, updated 21 November 2025, and understanding your annual water quality report, updated 17 November 2025.

How to read the table without a chemistry degree

Three columns carry the meaning, and they are usually next to each other.

• MCL, the maximum contaminant level. The legal ceiling. A number at or under it is compliant.
• MCLG, the goal. The level at which there is no known health risk, with a margin. For some contaminants the goal is zero and the legal limit is not, which is not a scandal, it is the difference between what is ideal and what is achievable at scale.
• The detected level, and the range. A single average can hide a bad month. The range is the honest column.

Units trip people up: ppm is milligrams per litre, ppb is micrograms per litre, and a thousand ppb is one ppm. Nitrate is reported at 10 ppm as the limit; arsenic at 0.010 ppm, which is 10 ppb. If the two are printed in different units on the same page, you are not confused, the table is.

Limits from the EPA National Primary Drinking Water Regulations, page updated 31 August 2026.

What changes in 2027

The EPA finalised a revision of the rule, announced on 15 May 2024. The changes people will notice: systems serving more than 10,000 customers will send the report twice a year instead of once, there will be more information about lead, and there is a push toward plain language and translations. The EPA says the easier to read reports start in 2027.

EPA, Consumer Confidence Report rule revisions, page updated 21 November 2025. We did not state the rule's effective date or the exact delivery dates for the twice yearly reports: the Federal Register text was not readable from here and we will not quote a date we did not see.

The report does not cover everything, and does not cover you if you have a well

Two limits worth knowing. First, the report lists regulated contaminants. Something unregulated can be present and legitimately absent from the table. Second, none of this applies to a private well: no report, no schedule, no limits that bind. That is a different job, and it is yours. See testing your well water and well water or city water.

If your report shows something you want to reduce at the tap, or if you are on a well and treating your own water, our treatment dose calculator gives the federal dose for the container you have, and says plainly what none of it removes.

Sources, with the date of each

• EPA, CCR information for consumers, page updated 21 November 2025.
• EPA, understanding your annual water quality report, page updated 17 November 2025.
• EPA, Consumer Confidence Report rule revisions, page updated 21 November 2025; final rule announced 15 May 2024.
• EPA, National Primary Drinking Water Regulations, page updated 31 August 2026.
• EPA report lookup tool, page updated 9 September 2026.