Water Preparedness
Understand what's in your water.
Your utility tests your water and publishes the results every year. Most people never read them. This guide teaches you how to find your water quality report, understand what the numbers mean, and decide whether your household needs additional treatment.
Your Annual Report
The Consumer Confidence Report: your water's scorecard
Every community water system in the United States that serves at least 25 year-round residents must publish an annual drinking water quality report, called a Consumer Confidence Report (CCR). This requirement comes from the Safe Drinking Water Act, and your utility must deliver the report to customers by July 1 each year.[1]
The CCR covers the previous calendar year's testing results. The report arriving in summer 2026 reflects water quality data from 2025. It tells you where your water comes from, what contaminants were detected, how those levels compare to federal and state standards, and what treatment your utility uses.
Start here. Before buying a filter, before worrying about PFAS, before testing your own water, read what your utility already knows and has already published.
If you own your home
Check your mail, your email inbox, or your online utility account. Your CCR may arrive as a printed mailer, a PDF attachment, or a link on your water bill. Many utilities post it on their website under "water quality" or "annual report."
Search online: "[your utility name] Consumer Confidence Report" or "[your city] water quality report."
If you rent
The report goes to whoever pays the water bill. In an apartment building, that is usually the property management company. Ask your landlord or building manager for a copy.
You can also find it yourself by identifying the water utility from your building's address and searching for their CCR online.
If you have a private well
Private wells are not covered by the Safe Drinking Water Act. You will not receive a CCR because no one tests your water but you. You are responsible for testing and treatment.
See our well water preparedness guide for testing schedules and our water testing guide for how to test.
EPA lookup tool
The EPA maintains a resource at epa.gov/ccr to help you locate your utility's report by state. The EPA's Safe Drinking Water Hotline is also available at 1-800-426-4791 for questions about drinking water quality and federal standards.[2]
Reading the Report
What the numbers in your CCR mean
A CCR looks technical at first glance, but it follows a standard format. Once you know the key columns, you can evaluate your water quality in about ten minutes.
Water source
The report identifies where your water comes from: surface water (rivers, lakes, reservoirs), groundwater (wells, aquifers), or a combination. The source affects what kinds of contaminants are possible. Surface water systems are more vulnerable to agricultural runoff and microbial contamination. Groundwater sources are more susceptible to naturally occurring minerals, nitrates, and in some regions, arsenic or radon.
The contaminant table
This is the core of the report. It lists each contaminant detected, along with several columns:
| Column | What it means |
|---|---|
| Contaminant | The name of the substance detected. Examples: lead, total trihalomethanes, nitrate, barium, fluoride. |
| MCL | Maximum Contaminant Level. The highest concentration legally allowed. This is the enforceable standard. |
| MCLG | Maximum Contaminant Level Goal. The level below which no known health risk exists. Not enforceable. Often lower than the MCL, and sometimes zero. |
| Your level (or range) | What was actually detected in your water system. Often shown as a range across sampling locations, with the highest single result noted. |
| Violation? | Whether the detected level exceeds the MCL. A "No" means your water met the legal standard. A detected level above the MCLG but below the MCL is legal but worth understanding. |
MCL vs. MCLG: why the two numbers matter
The gap between the MCL and the MCLG is where individual households make their own decisions. The MCL is set considering what is feasible for utilities to achieve at a reasonable cost. The MCLG is set purely on health. When the two numbers differ significantly, it means the enforceable standard allows some level of a contaminant that the health goal says should be lower.
The most important example: the MCLG for lead is zero. There is no safe level of lead exposure. But the action level that triggers utility response under the Lead and Copper Rule is 15 parts per billion (ppb), and the 2024 Lead and Copper Rule Improvements lower this to 10 ppb, with full compliance required by November 2027.[3] If your CCR shows lead at 8 ppb, that is legal, but it is not zero.
What "no violation" actually means
"No violation" means your water met every legally enforceable standard. For most households, this represents safe drinking water. The standards cover more than 90 regulated contaminants, and the testing is rigorous.
But the standards are not zero for most contaminants, and some substances are detected in drinking water that are not yet regulated at all. Meeting the standard is the baseline, not the ceiling. Your CCR gives you the information to decide whether your household's situation calls for anything beyond that baseline.
What to Look For
Contaminants that matter most for households
Not every contaminant on your CCR demands attention. Some are treatment byproducts that are well-controlled. Others are naturally occurring minerals within safe ranges. Focus on these categories, which are the ones most likely to affect household decisions about filtration.
Lead
Lead enters drinking water through corrosion of older pipes, fittings, and solder, not from the water source itself. Homes built before 1986 are most at risk. The MCLG is zero. The current action level is 15 ppb, dropping to 10 ppb under the LCRI by 2027.[3] EPA has mandated that all lead service lines be replaced within 10 years.
What you can do: Run cold water for 30 seconds before drinking if your home has older plumbing. Use only cold water for cooking and drinking, as hot water dissolves lead more readily. A filter certified to NSF/ANSI 53 for lead provides point-of-use protection while infrastructure is updated.
PFAS (per- and polyfluoroalkyl substances)
PFAS are a group of synthetic chemicals used in non-stick coatings, waterproof fabrics, and firefighting foam. They are called "forever chemicals" because they do not break down in the environment. In April 2024, the EPA established the first enforceable drinking water standards for PFAS, setting MCLs of 4 parts per trillion for PFOA and PFOS, with MCLGs of zero for both.[4]
In May 2025, EPA announced it will retain the PFOA and PFOS standards but extend the compliance deadline to 2031 and reconsider standards for four other PFAS.[5] Public water systems must monitor for PFAS and complete initial monitoring by 2027.
What you can do: Check your CCR for PFAS results. If your utility has not yet reported PFAS data, monitoring is still being implemented. Filters certified to NSF/ANSI 53 for PFAS or NSF/ANSI 58 (reverse osmosis) can reduce PFOA and PFOS. Activated carbon filters, particularly carbon block and granular activated carbon, are effective for PFAS at the concentrations found in most drinking water.
Disinfection byproducts (THMs and HAAs)
When chlorine or chloramine reacts with organic matter in the water, it produces disinfection byproducts. The two main groups are total trihalomethanes (TTHMs) and haloacetic acids (HAA5). Both are regulated, with MCLs of 80 ppb for TTHMs and 60 ppb for HAA5. Long-term exposure above these levels is associated with increased cancer risk.
What you can do: Disinfection byproducts are common in surface water systems. A carbon filter (NSF/ANSI 42 for chlorine taste and odor, NSF/ANSI 53 for THMs specifically) can reduce them at the tap. The tradeoff is real: chlorine disinfection is what keeps your water free of bacteria and viruses between the treatment plant and your faucet. Reducing disinfection byproducts does not mean disinfection is bad.
Nitrate
Nitrate enters water from agricultural fertilizers, animal waste, and septic system effluent. The MCL is 10 mg/L (ppm). Nitrate is most dangerous for infants under six months, where high levels can cause "blue baby syndrome" by interfering with the blood's ability to carry oxygen. The MCLG equals the MCL at 10 mg/L because the standard is already set at the health-protective level.[6]
What you can do: Boiling water does not remove nitrate; it concentrates it. Reverse osmosis (NSF/ANSI 58) is the most effective residential treatment. Ion exchange systems can also reduce nitrate. If you have an infant and your water is near the 10 mg/L limit, use bottled water for formula until the issue is resolved.
Arsenic
Arsenic occurs naturally in groundwater in many regions, particularly in the western United States. The MCL is 10 ppb. The MCLG is zero. Long-term exposure to arsenic above the MCL is associated with cancer, cardiovascular disease, and neurological effects.
What you can do: Standard carbon filters do not effectively remove arsenic. Reverse osmosis (NSF/ANSI 58) is the most reliable residential method. Some specialty adsorptive media filters are designed for arsenic removal. If your CCR or well test shows arsenic, choose a treatment method specifically certified for arsenic reduction.
Copper
Like lead, copper enters water through corrosion of household plumbing, not from the source water. The action level is 1.3 mg/L (ppm). Short-term exposure above the action level can cause gastrointestinal distress. Blue-green staining on fixtures is a visible sign of elevated copper.
What you can do: Running cold water for 30 seconds before use flushes the water that has been sitting in contact with copper pipes. Reverse osmosis and some carbon block filters certified for copper can provide additional reduction.
Choosing a Filter
NSF certifications: match the filter to the contaminant
Water filter marketing is full of unverifiable claims. The only reliable way to know whether a filter does what it says is an independent certification, and in the United States, that means NSF/ANSI. If a filter does not carry the relevant NSF certification for the contaminant you care about, treat its claims as unproven.
Aesthetic effects
Covers taste, odor, and chlorine reduction. This is the baseline certification for any carbon filter. If your water tastes or smells like chlorine, this is what you need. It does not cover health-related contaminants.[7]
Common filter types: pitcher filters, faucet-mount filters, refrigerator filters
Health effects
Covers health-related contaminants: lead, VOCs, cysts (Giardia, Cryptosporidium), mercury, asbestos, and PFAS (since the P473 protocol was folded in). This is contaminant-specific. A filter certified to NSF 53 for lead may not also be certified for VOCs. Check the specific claims.[7]
Common filter types: under-sink carbon block, countertop filters, some pitcher filters
Reverse osmosis
The broadest standard. Certifies entire reverse osmosis systems for total dissolved solids, plus optional claims for arsenic, fluoride, nitrate, lead, hexavalent chromium, and PFAS. If you need to remove a contaminant that carbon filters cannot handle, particularly fluoride, nitrate, or arsenic, an NSF 58 certified RO system is the standard residential solution.
Common filter types: under-sink RO systems, countertop RO units
Emerging contaminants
Covers trace pharmaceuticals, herbicides, pesticides, and personal care product chemicals that are increasingly detected in drinking water as testing methods improve. These are "contaminants of emerging concern," detected at trace levels that may affect some consumers' perception of water quality.[7]
Fewer filters carry this certification. Look for it specifically if your water supply is downstream of wastewater treatment plants.
How to verify a certification claim
A label that says "tested to NSF standards" or "NSF-grade" is not the same as "NSF certified." Genuine certification means the product was independently tested, verified, and is subject to ongoing monitoring by NSF International or another accredited certification body (WQA, IAPMO, UL).
Verify any NSF certification at NSF's product verification database. Search by manufacturer, product name, or standard number. If the product is not listed, the claim is not verified.
Making a Decision
Do I need additional treatment?
Most municipal water in the United States meets all federal standards and is safe to drink as delivered. Additional treatment is a personal household decision, not a universal requirement. Here is a framework for making that decision based on your CCR results and your household's situation.
1. Read your CCR and note any detected contaminants
Pay attention to contaminants that are detected at levels between the MCLG and the MCL. These are legal but not at the health-goal level. Also note any contaminants detected "below the MCL" without a specific number provided; ask your utility for the actual measured value.
2. Consider your household's specific vulnerabilities
Some household members face higher risk from certain contaminants. Infants under six months are vulnerable to nitrate. Pregnant women are advised to minimize lead exposure. Immunocompromised individuals (chemotherapy patients, people with HIV, organ transplant recipients) may need additional microbial protection beyond what municipal treatment provides.
If your household includes anyone in these categories, review your CCR with their specific vulnerabilities in mind. The EPA and CDC both recommend that immunocompromised individuals consult their healthcare provider about whether additional water treatment is warranted.
3. Evaluate your home's plumbing
Your CCR measures water quality at sampling points in the distribution system, not at your specific tap. Lead and copper contamination happens between the main and your faucet, through lead service lines, lead solder, and brass fixtures. If your home was built before 1986, consider having your tap water tested for lead independently.
Your utility is now required to inventory all lead service lines and is mandated to replace them within 10 years under the 2024 LCRI.[3] Contact your utility to find out whether your service line has been identified as lead, galvanized, or unknown.
4. Match any treatment to a specific contaminant
A filter is a tool with a specific purpose, not a general-purpose safety device. "Filtered water" is meaningless without knowing what was filtered and what certification proves it. Start from the contaminant you want to address, find the NSF standard that covers it, and buy a filter certified to that standard for that contaminant.
Our home water filtration guide covers the full range of residential treatment options. Our reverse osmosis guide covers the broadest-spectrum option.
Private Wells
If your water comes from a well
About 43 million Americans get their drinking water from private wells. Private wells are not regulated by the EPA and are not subject to the Safe Drinking Water Act. No one tests your water unless you arrange it yourself. No one sends you an annual quality report. The responsibility for water quality belongs entirely to the well owner.[8]
Minimum testing schedule
The EPA recommends testing well water at least once a year for total coliform bacteria, nitrate, total dissolved solids, and pH. Additional testing depends on your region and circumstances:
- Test for arsenic if you are in a region with naturally occurring arsenic (common in parts of the West, Midwest, and New England).
- Test for radon if your area has known radon risk.
- Test for pesticides and herbicides if your well is near agricultural land.
- Test for volatile organic compounds if your well is near industrial sites, gas stations, or dry cleaners.
- Test immediately after any flood, nearby construction, changes in taste or odor, or an unexplained illness in the household.
Your state or county health department can provide guidance on which contaminants are most relevant in your area. Many county cooperative extension offices offer water testing services or can direct you to certified laboratories. Our water testing guide covers how to collect samples, where to send them, and how to interpret the results.
Our well water preparedness guide covers the full picture for well owners: backup power for the pump, hand pump alternatives, testing schedules, and treatment options specific to well water.
Take Action
Five things you can do this week
Find and read your CCR
Search "[your utility name] Consumer Confidence Report" or check your utility's website. Read it once. It takes ten minutes.
Note any contaminants between MCLG and MCL
These are legal but above the health goal. Write them down. They are the starting point for any filtration decision.
Check your home's plumbing age
If your home was built before 1986, consider a first-draw lead test. Your utility may offer free lead testing kits.
Ask about your service line
Contact your utility and ask whether your service line has been identified in the lead service line inventory. Know what connects your house to the main.
If you have a well, schedule a test
Contact your county health department or cooperative extension office. Annual testing for bacteria and nitrate is the minimum.
Sources
- EPA. "Consumer Confidence Report Rule Revisions." epa.gov. Accessed August 2026.
- EPA. "Understanding Your Annual Water Quality Report." epa.gov. Accessed August 2026.
- EPA. "Lead and Copper Rule Improvements (LCRI)." Federal Register, October 30, 2024. epa.gov. Accessed August 2026.
- EPA. "PFAS National Primary Drinking Water Regulation." Final rule, April 26, 2024. epa.gov. Accessed August 2026.
- EPA. "EPA Announces It Will Keep Maximum Contaminant Levels for PFOA, PFOS." May 14, 2025. epa.gov. Accessed August 2026.
- EPA. "National Primary Drinking Water Regulations." epa.gov. Accessed August 2026.
- NSF International. "NSF/ANSI 42, 53, and 401: Filtration Systems Standards." nsf.org. Accessed August 2026.
- EPA. "Private Drinking Water Wells." epa.gov. Accessed August 2026.
Keep Going
Next steps in water preparedness
Water testing guide
How to test your own water, where to send samples, and how to interpret the results for both municipal and well water.
Home water filtration
The full range of residential filtration options, from pitcher filters to whole-house systems, matched to what they actually remove.
Well water preparedness
Testing schedules, backup power for well pumps, hand pump alternatives, and treatment options specific to well owners.