Every municipal water utility in the United States is required by the EPA to send customers an annual Consumer Confidence Report (CCR) — also called a water quality report — by July 1st each year. Most people glance at it and throw it away. But knowing how to read it tells you exactly what is in your water, whether any contaminants are approaching concerning levels, and whether you actually need a water filter. Here is how to interpret what you are looking at.
Where to Find Your Report
Your utility is required to mail or email the report annually. You can also find it online at epa.gov/ccr by searching your zip code or utility name. If you rent, your landlord may receive it instead — you have the legal right to request a copy.
Understanding the Layout
CCRs vary in format but always include the same core information:
- Source of your water (groundwater, surface water, or a combination)
- A table of detected contaminants with levels and legal limits
- Any violations that occurred during the reporting year
- General information about the water system and treatment methods
The Contaminant Table: What Each Column Means
The main table is the most important part of any CCR. Here is what each column typically contains:
Contaminant name
The chemical or substance detected. Common entries include:
- Total Trihalomethanes (TTHM) — disinfection byproducts from chlorine reacting with organic matter
- Haloacetic Acids (HAA5) — another group of chlorine disinfection byproducts
- Nitrates — common in agricultural areas from fertilizer runoff
- Lead and Copper — from household plumbing, not the water supply itself
- Total Coliform / E. Coli — bacterial indicator tests
- Fluoride — added deliberately at low levels for dental health
MCLG (Maximum Contaminant Level Goal)
This is the level at which no known or anticipated health effects occur, with a margin of safety. It is a non-enforceable health goal set by the EPA. Some MCLGs are zero (for carcinogens like certain pesticides and lead) because no level is considered safe.
MCL (Maximum Contaminant Level)
This is the legally enforceable limit — the highest concentration of a contaminant allowed in drinking water. MCLs are sometimes higher than MCLGs because achieving the MCLG may be technically or economically impossible. Your utility must keep contaminants at or below the MCL.
Level Detected
The actual level found in your water during the reporting period. This is usually shown as a range (lowest to highest sample) or a single average. The unit is typically:
- mg/L (milligrams per liter) — same as parts per million (ppm)
- µg/L (micrograms per liter) — same as parts per billion (ppb)
- pCi/L (picocuries per liter) — used for radioactive contaminants
- NTU (Nephelometric Turbidity Units) — used for turbidity (cloudiness)
Violation (Yes/No)
A “Yes” here means your utility exceeded the legal limit for that contaminant at some point during the reporting year. This does not necessarily mean the water is currently unsafe — utilities are required to notify customers of violations immediately — but it is worth following up with your utility for context.
What to Pay Attention To
Look for levels close to the MCL
Even if a contaminant is technically within legal limits, a level detected at 80% or 90% of the MCL is worth noting. Levels fluctuate, and today’s compliant water could exceed limits during different seasons or conditions.
Lead and copper are reported differently
Lead and copper come from household plumbing and fixtures, not the treatment plant. The CCR shows the 90th percentile result from tap sampling at customer homes. The Action Level for lead is 15 ppb — if more than 10% of tested homes exceed this, the utility must take action. Importantly, even a zero reading in the CCR does not guarantee your home has no lead risk if it has older plumbing.
Disinfection byproducts (TTHMs and HAA5s)
These form when chlorine reacts with naturally occurring organic matter. They are worth watching, particularly if you are pregnant or have young children. Both have MCLs of 80 µg/L and 60 µg/L respectively.
Any violation in the last 12 months
If there was a violation — even a minor monitoring violation — read the details. Your utility is required to explain what happened and what was done to correct it.
What the CCR Does Not Tell You
The CCR reflects water quality at the treatment plant or distribution system, not necessarily at your tap. Contaminants can enter your water between the mains and your faucet from old service lines or household plumbing. If you have any of the following, consider a home test regardless of what the CCR shows:
- A home built before 1986 with original plumbing
- A private well (CCR does not apply to wells)
- A history of pipe corrosion or discolored water
Bottom Line
Your CCR is a valuable and free resource. Read the contaminant table, compare levels to the MCL, and flag anything detected near the limit or listed as a violation. If your report shows contaminants you are concerned about, use the information to select the right water filter rather than guessing. And remember that the CCR is a starting point — it does not replace in-home water testing, especially for lead.
Disclaimer: If your CCR shows violations or elevated contaminants, contact your local utility and consider having your water independently tested by a certified laboratory.