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Understanding Your Water Quality Report

Water quality reports can be confusing with their technical terms and scientific measurements. This guide helps you understand what those numbers mean and how they affect your water safety.

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Key Components of a Water Quality Report
Understanding Water Quality Measurements
How to Read Your Report
Common Contaminants to Look For
Next Steps After Reading Your Report
Get Expert Help with Your Water Quality

Key Components of a Water Quality Report

Every year, public water systems publish Consumer Confidence Reports (CCRs), also known as Water Quality Reports. These reports provide crucial information about your local drinking water quality, including where your water comes from, what's in it, and how it compares to federal and state standards.

Sample Water Quality Report Section
REGULATED SUBSTANCES
Substance
Year
Sampled
MCL
[MRDL]
Amount
Detected
Violation
Chlorine (ppm)
2023
[4]
1.2
No
Fluoride (ppm)
2023
4
0.7
No
HAAs (ppb)
2023
60
32
No
Lead (ppb)
2023
15
3
No
This is an example of how contaminant information appears in a typical water quality report

Contaminant Levels

Reports list the amount of regulated contaminants detected in your water supply. These are measured in units like parts per million (ppm), parts per billion (ppb), or milligrams per liter (mg/L).

Key insight: Pay attention to both the detected levels and when the testing occurred. Water quality can change over time, so more recent test results are more relevant to your current water quality.

Maximum Contaminant Levels (MCLs)

The EPA sets legal limits for each contaminant, known as Maximum Contaminant Levels. Your report will show how your water compares to these standards, indicating if levels exceed safety thresholds.

Important note: MCLs are regulatory standards, not necessarily health-based ideals. Some contaminants may have health effects even at levels below the legal MCL, especially for vulnerable populations.

Common MCL Examples:

  • Lead: 15 ppb (action level)
  • Arsenic: 10 ppb
  • Trihalomethanes: 80 ppb
  • Haloacetic Acids: 60 ppb
  • Nitrates: 10 ppm

Health Effects Information

Reports include information about potential health effects of detected contaminants, especially if they exceed regulatory limits. This helps you understand the implications for your family's health.

Short-term Effects

Immediate health concerns that might appear shortly after exposure to certain contaminants, such as gastrointestinal illness from microbial contaminants.

Long-term Effects

Health issues that may develop after years of exposure to low levels of certain contaminants, such as increased cancer risk or developmental issues.

Source Water Assessment

Many reports include information about your water's source (groundwater, surface water, etc.) and any vulnerabilities to potential contamination sources.

Why this matters: Understanding your water source helps you recognize potential contamination risks. For example, agricultural areas may have higher nitrate levels, while urban areas might have more industrial contaminants.

Violations and Compliance

If your water system violated any drinking water standards, the report must explain the violation, potential health effects, and steps being taken to correct the issue.

Health-Based Violations

Occur when contaminant levels exceed MCLs or when treatment techniques aren't followed, potentially posing health risks.

Monitoring Violations

Occur when a water system fails to test for certain contaminants or doesn't report results correctly.

Understanding Water Quality Measurements

Parts Per Million (ppm) or Milligrams Per Liter (mg/L)

These equivalent measurements represent one part contaminant per million parts water. For perspective, 1 ppm is like 1 minute in 2 years or a single penny in $10,000.

Common contaminants measured in ppm include chlorine, fluoride, nitrates, and hardness minerals like calcium.

Parts Per Billion (ppb) or Micrograms Per Liter (μg/L)

These measurements represent one part contaminant per billion parts water. To visualize: 1 ppb is like 1 second in 32 years or a single drop in an Olympic-size swimming pool.

Heavy metals (lead, arsenic), pesticides, and PFAS are typically measured in ppb due to their potential toxicity at very low levels.

Measurement Conversion Guide

Understanding the relationship between different units can help you interpret your water report:

  • 1 ppm = 1,000 ppb
  • 1 mg/L = 1 ppm
  • 1 μg/L = 1 ppb

Why it matters: The smaller the measurement unit, the more sensitive the test. Some contaminants are measured in ppb because they can affect health at extremely low concentrations. Always check which unit is being used when comparing levels to safety standards.

How to Read Your Report

Water quality reports can be several pages long and filled with tables and technical information. Follow these steps to make sense of the information that matters most to you:

1

Start with the Summary

Most reports begin with a summary that highlights key findings and whether your water meets all standards. This gives you a quick overview before diving into details.

2

Check for Violations

Look for any mentions of violations or exceedances. These indicate areas where the water system failed to meet regulatory standards and should be given priority attention.

3

Review Contaminant Tables

Examine the detailed tables showing detected contaminants. For each contaminant, compare the detected level to the MCL to understand how close it is to the regulatory limit.

4

Note Testing Dates

Check when tests were conducted. More recent tests provide a better picture of your current water quality than tests from several years ago.

Priority Checklist: Key Contaminants to Focus On

While all information in your report is important, pay special attention to these high-priority contaminants that can have significant health impacts:

Lead and Copper

Neurotoxins that can affect development, especially in children.

Health concern even at low levels

Arsenic

Naturally occurring element linked to cancer and other health issues.

Long-term exposure risk

Nitrates

Can cause "blue baby syndrome" and other health problems.

Acute risk for infants

Disinfection Byproducts

THMs and HAAs formed during water treatment.

Linked to cancer with long-term exposure

PFAS

"Forever chemicals" increasingly found in water supplies.

Emerging contaminant of concern

Coliform Bacteria

Indicator of possible disease-causing organisms.

Immediate health concern

Important Reminder

Remember that legal limits (MCLs) aren't always the same as health-based guidelines. Some contaminants may be legal at current levels but still present health concerns according to the latest research. The Environmental Working Group (EWG) often publishes more stringent health-based guidelines than regulatory MCLs.

Common Contaminants to Look For

Lead and Copper

Lead and copper are common contaminants found in drinking water. High levels of lead can be particularly harmful to children, as it can affect their development and lead to learning disabilities.

Arsenic

Arsenic is a naturally occurring element that can be found in groundwater. High levels of arsenic can increase the risk of various health issues, including cancer.

Nitrates

Nitrates are a type of contaminant found in drinking water. High levels of nitrates can pose a risk to infants, as they can lead to a condition called "blue baby syndrome."

Disinfection Byproducts

Disinfection byproducts are chemicals formed when chlorine is used to disinfect drinking water. Some of these chemicals, such as trihalomethanes (THMs) and haloacetic acids (HAAs), can pose health risks if consumed in high amounts.

PFAS

PFAS are a group of chemicals that are often found in drinking water. They are known as "forever chemicals" because they can persist in the environment and in the human body for a long time.

Coliform Bacteria

Coliform bacteria are a group of bacteria found in the natural environment. High levels of coliform bacteria can indicate the presence of harmful bacteria, which can cause gastrointestinal illness.

Next Steps After Reading Your Report

Once you've reviewed your water quality report, you may have concerns or questions about your water safety. Here are some practical steps you can take to ensure your family has clean, safe drinking water:

Get Independent Testing

For peace of mind, consider getting your water independently tested, especially if you're concerned about specific contaminants or have a private well.

When to consider independent testing:

  • Your water has an unusual taste, smell, or appearance
  • You have a private well (not covered by municipal reports)
  • Your home has older plumbing that may contain lead
  • You live near industrial or agricultural areas
  • You want to test for contaminants not covered in your CCR
Explore water testing options

Explore Filtration Options

Research water filtration systems designed to address the specific contaminants found in your water. Not all filters remove all contaminants.

Matching filters to contaminants:

  • • Activated Carbon: Chlorine, pesticides, VOCs
  • • Reverse Osmosis: Heavy metals, nitrates, PFAS
  • • Ion Exchange: Hardness minerals, radium
  • • UV Disinfection: Bacteria, viruses
  • • Distillation: Multiple contaminants
View filtration comparison guide

Ask Questions

Contact your water utility with specific questions about your report. They are required by law to provide information about water quality.

Questions to ask your utility:

  • How often is testing conducted for [specific contaminant]?
  • What steps are being taken to address [contaminant] levels?
  • Where exactly does my water come from?
  • Are there plans to upgrade treatment facilities?
  • Does the utility offer any assistance programs for filtration?
Find your local water utility contact

Stay Updated

Water quality can change over time. Review your annual report each year and stay informed about local water quality issues.

Resources to stay informed:

  • Sign up for alerts from your water utility
  • Follow local news about water quality issues
  • Check the EPA's Safe Drinking Water Information System
  • Review the EWG's Tap Water Database for updates
  • Join community water quality groups
Access water quality resources

Frequently Asked Questions

How often are water quality reports published?

Community water systems are required to provide Consumer Confidence Reports (CCRs) to their customers annually, typically by July 1st of each year. These reports cover the water quality data from the previous calendar year. If you haven't received your report, contact your water utility or check their website, as many publish their reports online.

What if my water comes from a private well?

Private wells are not regulated by the EPA and do not receive water quality reports. If you have a private well, it's your responsibility to test your water regularly. The EPA recommends testing for bacteria, nitrates, and any contaminants of local concern at least once a year, and more frequently if you notice changes in water quality, after flooding, or if someone in your household experiences recurring gastrointestinal illness.

What's the difference between primary and secondary standards?

The EPA establishes two types of drinking water standards:

  • Primary Standards: These are legally enforceable standards that apply to public water systems. They protect public health by limiting the levels of contaminants that can adversely affect public health.
  • Secondary Standards: These are non-enforceable guidelines for contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. Water systems are not required to comply with these, but some states may choose to adopt them as enforceable standards.

Should I be concerned if contaminants are detected but below MCLs?

Not necessarily, but it depends on the specific contaminant and your health situation. MCLs are set with safety margins, but some health researchers and organizations like the Environmental Working Group (EWG) suggest that certain contaminants may pose health risks even at levels below regulatory limits, especially with long-term exposure.

If you're pregnant, have young children, are immunocompromised, or have specific health concerns, you might want to consider additional filtration even for contaminants below MCLs. Consult with a healthcare provider if you have specific health concerns about your water quality.

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