How to read your water quality report in 10 minutes

Every community water system in the United States must send customers an annual water quality report, called a Consumer Confidence Report (CCR), by July 1 each year. Canadian municipalities publish similar annual reports under provincial rules. These reports are dense, but they’re the single best free source of information about what’s in your tap water.

This guide walks you through one, section by section, so you can find the answer you actually need.

Step 1: Find your report

You have four quick options:

1. Your water bill. The utility’s legal name is printed on it. Search that name plus “water quality report.”
2. Your utility’s website. Look under “Water Quality,” “Customers” or “Reports.” It’s often one click deeper than it should be.
3. The EPA’s lookup. The Find Your CCR tool lists reports by system.
4. Our city lookup. Each profile links straight to a search for the official report.

If you rent and your landlord pays for water, you can still find the report — it’s public. If you’re on a private well, there is no CCR; you’re responsible for testing (see our well water guide).

Step 2: Identify your water source

Near the front you’ll find where the water comes from: a river, lake, reservoir or groundwater aquifer, sometimes a blend. This matters:

• Surface water (rivers, lakes) is more exposed to runoff, algae and seasonal swings, and usually has more disinfection byproducts.
• Groundwater is naturally filtered but more likely to carry naturally occurring arsenic, radium, uranium, iron, manganese and hardness minerals.

Many reports also include a source water assessment — a summary of what could contaminate the source (farms, industry, septic systems, airports using firefighting foam).

Step 3: Learn the five acronyms that matter

Term	What it means
MCL (Maximum Contaminant Level)	The legal limit. Above it is a violation.
MCLG (MCL Goal)	The level with no known health risk. Not enforceable, but it tells you what “ideal” is — for lead and several carcinogens it’s zero.
AL (Action Level)	A trigger that forces the utility to act. Lead and copper use action levels, not MCLs.
MRDL	Maximum residual disinfectant level — the cap on chlorine or chloramine.
TT (Treatment Technique)	A required process instead of a number (common for turbidity and microbes).

Units trip people up. ppm = mg/L; ppb = µg/L (1,000 times smaller); ppt = ng/L (another 1,000 times smaller). PFAS limits are in ppt, which is why tiny numbers can still matter.

Step 4: Read the detected contaminants table

This is the heart of the report. For each contaminant, look at four columns:

1. Level detected (or average). Compare it to the MCL and the MCLG. A result under the MCL but well above the MCLG is legal but not ideal.
2. Range. A low average can hide high individual samples.
3. Violation (Yes/No). Any “Yes” deserves your attention and should be explained in the report.
4. Likely source. Tells you whether the problem is natural, industrial, agricultural or from your plumbing.

The lead row is different

Lead is reported as a 90th percentile value from homes most likely to have lead plumbing, plus the number of sites over the action level. The current action level is 15 ppb; under the Lead and Copper Rule Improvements it drops to 10 ppb on November 1, 2027. Crucially, the utility’s number is a system-wide statistic — your home could be much higher or lower. If your home was built before 1986 or your service line is unknown, test your own tap. Our lead guide explains how.

Step 5: Check the “unregulated” section

Many reports include results from EPA’s Unregulated Contaminant Monitoring Rule (UCMR). The fifth round (UCMR 5) covered 29 PFAS and lithium. Even where there’s no limit for a compound, these numbers help you decide whether a filter is worth it. PFOA and PFOS now have enforceable 4 ppt limits — see our PFAS guide.

Step 6: Read the notices and the fine print

Look for:

• Violations and explanations, including monitoring or reporting violations (the utility missed a test — not necessarily unsafe, but worth noting).
• Service line inventory information. Utilities had to publish lead service line inventories by October 2024 and must notify customers who have, or may have, lead lines.
• Special notices for vulnerable people, such as immunocompromised people and infants.

What to do with what you learn

If you see…	Do this
Lead 90th percentile above 5 ppb, or an older home	Test your own tap; use an NSF/ANSI 53 lead-certified filter meanwhile
PFOA/PFOS detected near or above 4 ppt	Consider an NSF/ANSI 58 reverse osmosis system or certified carbon block
High TTHMs or HAA5	A certified carbon filter (NSF/ANSI 53 VOC claim)
Nitrate above 5 mg/L and an infant at home	Use RO-filtered or bottled water for formula
Hardness above 120 mg/L	Run our softener payback calculator
Any violation you don’t understand	Call the utility — the contact number is required to be in the report

Bottom line

The CCR tells you about the water leaving the treatment plant and moving through the mains. It can’t tell you what your own pipes add. Use it to decide what to test for and which certified filter to buy — then verify at your tap if the stakes are high.