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Whether you are on city water or a private well, knowing what is in your tap water is the first step to protecting your family. This guide covers everything from choosing the right tests to interpreting results.
The most reliable way to test drinking water is a certified mail-in laboratory test, which checks for contaminants like lead, arsenic, nitrates, and bacteria with EPA-grade accuracy. Home test kits ($15–100) give a quick screen but are less precise. Testing runs about $15–200, and the 43 million Americans on private wells should test at least annually.
A certified laboratory test — often a convenient mail-in kit — is the most accurate. It measures exact levels of contaminants like lead, arsenic, nitrates, and bacteria using EPA-approved methods, rather than the pass/fail readout of a home strip.
It ranges from about $15–200. Basic home test kits run $15–100 and give a quick screen, while comprehensive certified lab panels typically run $50–200 depending on how many contaminants are included.
If you are on a private well, test at least once a year — plus after any change in taste, color, or odor, or nearby land use. Public-water customers can start with their utility's annual Consumer Confidence Report and test if they have older plumbing or specific concerns.
Even if your water comes from a municipal system that meets federal standards, testing your home water provides crucial information that utility reports cannot. Contaminants like lead enter water from your home plumbing after it leaves the utility's testing points.
Important: Private wells are not regulated by EPA. Well owners are solely responsible for testing and treating their water supply.
The most accurate option. State-certified labs use EPA-approved testing methods and provide precise measurements for comparison with regulatory limits.
Pros:
Details:
Good for basic screening and ongoing monitoring. Results are less precise but provide useful information quickly and affordably.
Types Available:
Details:
Your water utility is required to provide an annual Consumer Confidence Report showing contaminants detected at the system level.
What It Shows:
Limitations:
The contaminants you should test for depend on your water source, location, and concerns. Here are common testing panels:
| Test Panel | Includes | Best For | Cost |
|---|---|---|---|
| Basic | Bacteria, nitrates, pH, hardness | Private wells (annual) | $30-75 |
| Lead & Copper | Lead, copper | Older homes, municipal water | $25-50 |
| Heavy Metals | Lead, arsenic, mercury, chromium, cadmium | Industrial areas, mining regions | $75-150 |
| Comprehensive | 100+ contaminants including VOCs, pesticides | New homes, detailed analysis | $150-400 |
| PFAS | PFOA, PFOS, other forever chemicals | Near military bases, industrial sites | $200-400 |
Tip: Start by reviewing your water utility report to see what contaminants have been detected. Then test for lead/copper (home plumbing) and any contaminants of concern in your area.
Proper sample collection is critical for accurate results. Follow these steps carefully.
Use containers provided by or approved by your testing lab. Different tests may require different container types (some must be sterile, others require preservatives).
First-draw sample: Collect water that has been sitting in pipes 6+ hours (typically first thing in the morning). Used for lead and copper testing.
Flushed sample: Run water 2-3 minutes before collecting. Shows water quality from the main system, not home plumbing.
Label samples with date, time, and location. Some tests (especially bacteria) require samples to reach the lab within 24-48 hours. Keep samples cool but not frozen.
For Lead Testing: Collect a first-draw sample after water has sat in pipes at least 6 hours (overnight is ideal). This captures lead that has leached from pipes.
Your lab report will show detected contaminants and their concentrations. Here is how to interpret the key information:
MCL (Maximum Contaminant Level): The highest legally allowed level. Exceeding this triggers required action by water systems.
MCLG (Maximum Contaminant Level Goal): The level with no known health risk. Often lower than MCL; not enforceable.
ppb (parts per billion): Equivalent to micrograms per liter (ug/L). Very small concentrations.
ppm (parts per million): Equivalent to milligrams per liter (mg/L). 1 ppm = 1,000 ppb.
ND (Non-Detect): Contaminant not detected above the lab's detection limit. Does not mean zero.
Detection Limit: The lowest concentration the lab can reliably measure. Varies by test method.
EPA limits are legally enforceable but may not represent optimal health protection. Organizations like EWG publish stricter health guidelines based on current science. Compare your results to both.
Example: Your lead result of 5 ppb is below the EPA Action Level (15 ppb) but above the EWG health guideline (1 ppb). Consider treatment, especially if you have young children.
Call 800-426-4791 for referrals to state-certified labs in your area. This free service can help you find labs that test for specific contaminants.
Your state health department maintains a list of certified drinking water laboratories. Search "[your state] certified drinking water labs" or contact your state health department directly.
Many water utilities offer free or low-cost testing for customers, especially for lead and copper. Contact your utility's customer service department.
County or city health departments often provide testing services or referrals, particularly for private well owners.
Important: Look for labs certified for drinking water testing in your state. Certification ensures the lab uses EPA-approved methods and maintains quality control.
Stop drinking the water immediately. Use bottled water or boil water (for bacteria only). Contact your health department for guidance.
Flush water before use, use only cold water for drinking/cooking, and consider installing a certified filter. For high levels, stop using for consumption until filtered.
Research treatment options specific to your contaminant. Visit our water filters page for NSF-certified solutions. Consider consulting a water treatment professional.
After installing treatment, retest to confirm contaminants are reduced to safe levels. Test periodically to ensure ongoing effectiveness.
Start by reviewing what contaminants have been detected in your city's water supply, then decide what additional testing you need.
Match the certification to the contaminant: NSF/ANSI 42 covers aesthetic issues like chlorine taste and odor; NSF/ANSI 53 covers health-effects contaminants such as lead, arsenic, PFAS and VOCs; NSF/ANSI 58 covers reverse osmosis systems; NSF/ANSI 55 Class A covers UV disinfection; NSF/ANSI 401 covers emerging compounds like pharmaceuticals. A certification is claim-by-claim — a filter certified for chlorine is not thereby certified for lead — so read the listing for the exact contaminant your test found.
Certification listings are searchable on the NSF and Water Quality Association websites by brand and model. For product picks that carry the right claims, see our guide: Reverse osmosis vs. whole-house filtration.
This guide is for educational purposes only. For health concerns related to water contamination, consult with a healthcare provider. For technical guidance on well water or specific contamination issues, contact your state or local health department. Water quality testing should be performed by state-certified laboratories for accurate, actionable results.