Public water reporting guide

How to Read a Water Quality Report

A water quality report can be useful, but it is not always easy to understand. Here is what to look for first.

What is a water quality report?

A Consumer Confidence Report is an annual drinking-water report from a community water system. It usually describes where water comes from, what was detected in testing, how those results compare with standards, and whether the system had certain violations.

What to look for first

SectionWhy it matters
Water sourceShows whether water comes from surface water, groundwater, purchased water, or a blend.
Detected contaminants tableLists tested substances and measured levels.
ViolationsShows whether the system had certain reporting, monitoring, or health-based issues.
DefinitionsExplains units and standards such as MCL, MCLG, ppm, ppb, and pCi/L.

Common terms

MCL Maximum Contaminant Level: the highest level of a contaminant allowed in drinking water under a standard.

MCLG Maximum Contaminant Level Goal: a health-based goal, not always the enforceable limit.

ppm / ppb Parts per million or billion: common measurement units for contaminants.

CCR Consumer Confidence Report: the annual report provided by community water systems.

What a report cannot tell you

A water quality report is system-level information. It does not test your specific faucet. Plumbing, service lines, building age, private wells, and treatment equipment can affect what reaches your tap.

What to do next

If the report answers your question, use it as context. If you have a specific concern about your home, plumbing, taste, odor, hardness, lead, PFAS, nitrates, or a private well, testing may be the better next step.