Every public water system in the US is required by law to send customers an annual Consumer Confidence Report, or CCR. Also called a Water Quality Report. It covers everything detected in your water that year, over 90 regulated contaminants.
Most people throw it away.
That’s understandable. These reports are dense and use regulatory language that takes some practice to read. But once you know the structure, you can get through the key sections in about ten minutes.
Where to Find It
Your utility mails the CCR once a year, typically by July 1. If you pay a water bill, you should receive one. Renters sometimes don’t, your landlord or property manager gets it.
If you don’t have yours, a few options:
Your utility’s website almost always posts it. Search “[your city] water quality report [year]”. The EPA also maintains a database at epa.gov/ccr, searchable by state and utility name.
The easiest starting point for most people is EWG’s Tap Water Database. Search by zip code. It pulls data from your utility’s reports and lets you see it alongside EWG’s own health benchmarks. More on the difference between those benchmarks and EPA limits in a moment.
The Key Sections
Source Water Information
This tells you where your water comes from. The two main types are surface water (rivers, lakes, reservoirs) and groundwater (wells, aquifers).
Surface water sources tend to have more seasonal variation in quality. They pick up more organic matter, leaves, sediment, agricultural runoff, which matters because organic matter reacts with chlorine during disinfection to form byproducts called trihalomethanes (THMs). Groundwater is generally more stable but more vulnerable to contamination from local sources like old gas stations, farms, or industrial sites.
Knowing your source type gives context for what you’ll see in the contaminants table.
The Detected Contaminants Table
This is the core of the report. It lists every regulated contaminant that was detected, with several columns.
Contaminant name. Sometimes listed by chemical name, sometimes by common name. Lead, nitrate, arsenic, and total coliform are typical entries. Disinfection byproducts like total trihalomethanes (TTHMs) will appear if your water is chlorinated.
Unit of measurement. Usually parts per billion (ppb) or parts per million (ppm). Some contaminants are measured in parts per trillion (ppt), especially newer ones like PFAS. These units matter a lot, 10 ppb is a very different number from 10 ppt.
MCLG. The Maximum Contaminant Level Goal. This is the EPA’s health target, the level at which no known adverse health effects occur, with a margin of safety built in. For carcinogens, the MCLG is almost always zero. The EPA acknowledges no truly safe level.
MCL. The Maximum Contaminant Level. This is the actual enforceable legal limit. It’s set as close to the MCLG as is “feasible”, meaning the EPA factors in what treatment technology can realistically achieve and what it costs. A result at or below the MCL is legal. It doesn’t mean risk-free, especially when the MCLG for that contaminant is zero.
Your utility’s level. The measured concentration in your system’s water. Compare this to both the MCL and the MCLG.
Likely source. A brief note on where the contaminant typically comes from, erosion of natural deposits, agricultural runoff, industrial discharge, or disinfection byproducts. This helps you understand whether the contamination is local and controllable.
The Violations Section
If your utility had any violations during the reporting period, they must be disclosed here. Two types matter.
A health-based violation means a contaminant exceeded its MCL. That’s the more serious one. Your utility should have already notified you when it happened, but the CCR will spell it out.
A monitoring violation means the utility failed to test for something at the required frequency. Less immediately alarming, but it means there’s a gap in the data. You don’t know what wasn’t measured.
Either type is worth paying attention to.
MCLG vs. MCL: The Gap That Matters
Look at arsenic in your report if it appears. The MCLG is zero. The MCL is 10 ppb. That gap isn’t a mistake, it’s what the Safe Drinking Water Act was designed to produce. Congress told the EPA to set legal limits at the lowest feasible level, not at the theoretical health ideal.
The practical consequence: when a contaminant has an MCLG of zero and your utility reports a level below the MCL, your water is legal. But the EPA is also telling you, through the MCLG, that no level of that contaminant is without some risk.
This distinction matters most for carcinogens. Arsenic, benzene, PFAS, lead, all have MCLGs at or near zero. Staying below the MCL satisfies the law. It doesn’t guarantee no risk.
EWG vs. EPA Numbers
If you use EWG’s Tap Water Database, you’ll likely see some contaminants flagged as “above EWG guidelines” even when your utility is well within EPA limits. This confuses a lot of people.
EWG’s health guidelines are based on risk assessments that prioritize health targets, they’re closer to the MCLG than the MCL. They don’t account for treatment feasibility or cost. The EPA’s MCLs are regulatory compromises that factor in what’s achievable at scale.
Neither approach is wrong. They answer different questions. The EPA MCL answers: is this legal? EWG’s guideline answers: at what level does health risk drop to near-negligible? Both are useful. The confusion comes from treating them as competing versions of the same thing.
What CCRs Don’t Tell You
The CCR covers regulated contaminants in the treated water leaving your utility. Several important things fall outside that picture.
Private wells. If your home uses a private well, no CCR exists for your water. You’re responsible for testing it yourself. The testing section has guidance on what to test for and how.
Lead at the tap. Lead doesn’t come from your utility’s source water, it comes from pipes and plumbing inside your home. Your utility samples lead at a set of test taps around the system, but that number doesn’t reflect what comes out of your specific faucet. If your home was built before 1986, if you have lead service lines, or if you have older brass fixtures, test your tap directly.
Unregulated contaminants. The CCR only covers contaminants the EPA requires utilities to test for. PFAS compounds, for example, weren’t in most reports until the 2024 EPA rule required testing. There are chemicals in use today that utilities aren’t required to test for. PFAS and THMs are two categories worth reading up on separately.
What to Do With the Information
Read your CCR once a year. It takes ten minutes. Look at the contaminants table and ask two questions: what’s detected, and how close is it to the MCL?
If you see contaminants consistently near the MCL limit, especially carcinogens with an MCLG of zero, that’s a reasonable signal to consider a point-of-use filter for drinking water. A filter certified to remove specific contaminants adds a layer of protection beyond what treatment plants are required to provide.
If you see a health-based violation, act immediately. Don’t wait for guidance. Switch to bottled water or a verified filter until you confirm the issue is resolved. Then call your utility and ask what happened and what’s being done.
If you want to go deeper than the CCR, get your water tested directly. A lab test of your tap water captures what the CCR misses, including lead at the tap and some unregulated contaminants.
Sources: EPA Consumer Confidence Reports | EWG Tap Water Database | CDC: How to Read Your Drinking Water Quality Report