How to Read Your City’s Water Quality Report

Quick answer: How do you read a water quality report? Find the table of detected contaminants and compare each “Your Water” number with the maximum contaminant level (MCL), the highest level the law allows. Your water system has to send you this report, called a Consumer Confidence Report (CCR), every year by July 1.

In this short video, Roger Wakefield explains that every city water system has to publish a water quality report every year, called a Consumer Confidence Report, and why plumbers should read it with the customer before they test the water.

What is a water quality report?

A water quality report is a yearly report card on your drinking water. The U.S. Environmental Protection Agency (EPA) requires every community water system to deliver one to its customers, and the official name is the Consumer Confidence Report. You may also see it called the annual drinking water quality report.

A community water system is a public water system that serves the same people all year, like the city utility that sends you a water bill. The EPA counts a water system as public when it serves at least 15 service connections, or an average of at least 25 people for at least 60 days a year. There are over 148,000 public water systems in the United States.

Not everyone gets a report. If your water comes from a private well, you will not get one, because the report comes from a water system. If you rent, or live in an apartment or condo, the report may go to the owner instead of you, so ask your building manager or landlord, or look it up online.

When does the water quality report come out?

Your water supplier must send the report each year by July 1. The EPA’s quick reference guide for water systems says the July 1 report covers the calendar year before it, January 1 through December 31. A few more rules decide how you get it:

• Big systems: a system that serves 100,000 or more people must also post its current report on a website anyone can open.
• Small systems: a system that serves fewer than 10,000 people may publish the report in a local newspaper instead of mailing it, and one that serves 500 or fewer may send a notice that the report is available if you ask. Both need permission from the state’s governor or the person the governor picks.
• Changes on the way: the EPA finalized changes to the rule in 2024. Under them, systems that serve more than 10,000 customers must send the report twice a year, and starting in 2027 the reports are meant to be easier to read.

Where can you find your city’s water quality report?

There are several ways to get your report, and you only need one of them to work. Try these steps in order:

1. Watch your mail and your email around July 1. Water systems mail or hand deliver the report, and the EPA lets them send it electronically too.
2. Check your water system’s website. Systems that serve 100,000 or more people have to post the current report online.
3. Use the EPA’s search tool, linked from its page of CCR information for consumers.
4. Call your water supplier and ask for a copy. Water systems have to make copies available when you ask.
5. If you rent, ask your building manager or landlord for the report.

What must a water quality report include?

The EPA sets the basics every report must cover. States can add their own information, but they cannot leave out the federal list. According to the EPA, your report must include:

• The lake, river, aquifer (AK-wuh-fer) or other source of your water. An aquifer is an underground layer of rock, sand or gravel that holds water.
• A short summary of the risk of contamination to that source.
• The regulated contaminants found in your drinking water. A contaminant is any substance in the water besides the water itself, like a mineral, a chemical or a germ.
• The possible health effects of any contaminant found at a level that breaks an EPA health standard.
• What the water system is doing to restore safe drinking water.
• A statement for people at higher risk about avoiding Cryptosporidium (krip-toe-spo-RID-ee-um), a tiny parasite that can cause stomach illness.
• Information about nitrate, arsenic or lead where they may be a concern.
• Phone numbers for more information, including the water system’s own number and the EPA’s Safe Drinking Water Hotline, 1-800-426-4791.

The report also has to print the definitions of its key terms and tell you about any violations. You can read more on the EPA’s Consumer Confidence Reports page.

What do the terms in a water quality report mean?

The report is written in regulation language. These are the terms the EPA requires every report to define, in plain English:

• Maximum contaminant level goal (MCLG): the level of a contaminant below which there is no known or expected risk to health. It is a health goal with a margin of safety built in, not a legal limit.
• Maximum contaminant level (MCL): the highest level of a contaminant allowed in drinking water. MCLs are enforceable, which means a water system that goes over one is in violation. They are set as close to the MCLG as the best available treatment technology allows.
• Maximum residual disinfectant level goal (MRDLG): the level of a disinfectant below which there is no known or expected risk to health. A disinfectant is a chemical, like chlorine, that the water system adds to control germs.
• Maximum residual disinfectant level (MRDL): the highest level of a disinfectant allowed in drinking water. Residual means the amount still left in the water after treatment.
• Treatment technique (TT): a required process meant to reduce the level of a contaminant in drinking water. Some contaminants have a treatment technique instead of an MCL.
• Action level (AL): the amount of a contaminant that, if exceeded, triggers treatment or other steps the water system must follow. Lead and copper use action levels.
• Variances and exemptions: permission from the state or the EPA not to meet an MCL or a treatment technique under certain conditions.
• Level 1 assessment: a study of the water system to find possible problems and, if possible, why total coliform (KOH-lih-form) bacteria were found. Coliform bacteria are a group of germs used as a warning sign that other germs could be getting into the water.
• Level 2 assessment: a very detailed study to find out why an E. coli MCL violation happened, or why total coliform bacteria were found more than once. E. coli, short for Escherichia coli (esh-er-IK-ee-uh KOH-lye), is a type of coliform bacteria that comes from human or animal waste.

What do ppm, ppb and the other units mean?

Every number in the table comes with a unit, and the unit tells you how big the number really is. These are the units you will see most:

• ppm (parts per million): the EPA says milligrams per liter (mg/L) are the same as parts per million.
• ppb (parts per billion): a much smaller unit, used for contaminants that matter in tiny amounts. The arsenic MCL is 0.010 mg/L, which reports show as 10 ppb.
• ppt (parts per trillion): smaller still.
• pCi/L (picocuries per liter, PIE-koh-kyoor-eez): a unit that measures radioactivity in water.
• NTU (nephelometric turbidity unit, nef-uh-loh-MET-rik): a unit for turbidity, which means how cloudy the water is.
• ND (not detected): the lab did not find that contaminant in the samples.
• N/A (not applicable): that column does not apply to that contaminant.

How do you read the table of detected contaminants?

The table is the heart of the report. Read it one row at a time:

1. Find the contaminant’s name and the unit next to it.
2. Read the “Your Water” column. Some reports use another heading, such as level detected. It shows the highest level found during sampling.
3. Compare that number with the MCL or MRDL. If your water is above it, the system is in violation.
4. Compare it with the MCLG or MRDLG. Below the goal means no known or expected risk to health.
5. Read the range, which shows the lowest and highest levels found during sampling.
6. Check the violation column, which says yes or no, and the likely source of the contaminant.

Here is a row from the EPA’s own sample report. Chloramine, a disinfectant, shows an MRDLG of 4, an MRDL of 4 and a “Your Water” level of 1, with a range of 1 to 3. The level is under the limit, so the violation column says no.

Does the report show what comes out of your own faucet?

Not exactly. The report shows the results of the samples the water system took during the year. It cannot show what the pipes inside your own house add to the water on the way to your faucet.

Lead and copper are measured in tap water samples, and if more than 10% of those samples go over the action level, the water system must take extra steps. The EPA lists corrosion of household plumbing as a major source of both, and the MCLG for lead is zero. So the report is the starting point, not the last word. A test at your own home tells you about your own tap. You can see every limit on the EPA’s list of national primary drinking water regulations.

What should you do if your water quality report shows a violation?

Don’t panic, and don’t skip past it. The report has to tell you the possible health effects and what the water system is doing to restore safe drinking water. Then take these steps:

• Read the health effects language for that contaminant.
• Read what the water system says it is doing about it.
• Call the water system’s phone number in the report with your questions.
• Call the EPA’s Safe Drinking Water Hotline at 1-800-426-4791.
• If you are sensitive to contaminants or at higher risk of infection, talk with your doctor.

Why do plumbers read the water quality report before they test?

Roger’s advice to plumbers is simple: read the city’s water quality report with the customer first, then test. In his words, “Now they’re looking at their own city’s numbers, not hearing a salesman.”

Plumbers who want to learn water quality from Roger can start at the HALO Water Tour. Texas plumbers can also read Roger’s guide to the Texas plumbing license and water treatment, and anyone thinking about the trade can start with how to become a plumber.

Roger’s other training for tradespeople is on his site, he talks about the trades on The Trade Talks podcast, and you can find more plain-English guides on Roger’s blog.

Frequently asked questions about water quality reports

These are the questions homeowners ask most about their water quality report.

How often does my water quality report come out?

Once a year, by July 1. Under EPA rule changes finalized in 2024, systems that serve more than 10,000 customers must send it twice a year.

Do private well owners get a water quality report?

No. The report comes from a water system, so a home on a private well will not get one.

What is the difference between MCL and MCLG?

The MCLG is the health goal, the level with no known or expected risk to health. The MCL is the legal limit, set as close to the goal as the best available treatment technology allows. Going over the MCL is a violation.

What does ND mean on a water quality report?

ND means not detected. The lab did not find that contaminant in the samples it tested.

Who can I call with questions about my water quality report?

Start with the water system’s phone number printed in the report. You can also call the EPA’s Safe Drinking Water Hotline at 1-800-426-4791.

Who is Roger Wakefield?

Roger Wakefield is a Texas Master Plumber with 45 years in the trade, a blue-collar keynote speaker and one of the most watched trades educators in the world, with 1.7 million followers and more than 160 million YouTube views.

About Roger Wakefield

Roger Wakefield has spent 45 years in plumbing. Today he teaches the trades to 1.7 million followers across social media, on his YouTube channel and on The Trade Talks podcast. Read Roger’s story, or watch his videos on YouTube.