Home Water Testing: A Complete Guide
Everything you need to know about testing your tap water—when to test, what to test for, and how to understand your results.
Water Quality Analysis
Expert Reviewed
This content has been reviewed by Dr. Sarah Chen, PhD, Environmental Science Advisor, to ensure accuracy and alignment with current environmental science standards.
Last reviewed: February 2026
Why Test Your Water?
Your water utility tests water at the treatment plant, but many contaminants enter water AFTER it leaves the plant—from distribution pipes, service lines, and your home's plumbing. Additionally, private wells aren't regulated and require homeowner testing.
Key Reasons to Test:
- Municipal water reports don't show what comes out of YOUR tap
- Lead, copper, and bacteria can leach from your home's plumbing
- Well water is your responsibility—no utility tests it for you
- Contamination can occur after water main breaks or construction
- Vulnerable populations (children, pregnant women) need extra assurance
- Taste, odor, or appearance issues indicate potential problems
- Emerging contaminants like PFAS may not be included in utility reports
The EPA estimates that 15 million U.S. households rely on private wells, and millions more live in homes with lead service lines or aging plumbing. Testing is the only way to know if your water is truly safe.
When You Should Test Your Water
Test Immediately If:
You have a private well
Test annually for bacteria, nitrates, and basic contaminants. Test more frequently if you notice changes.
Your home was built before 1986
Likely has lead pipes, solder, or fixtures. Test for lead especially if you have children.
You're pregnant or have young children
Even low levels of contaminants like lead, nitrates, or bacteria are concerning for vulnerable populations.
Water has unusual taste, smell, or appearance
Metallic taste, chlorine smell, discoloration, or cloudiness can indicate contamination.
You live near potential contamination sources
Military bases, airports, farms, industrial facilities, landfills, gas stations, or dry cleaners.
Recent plumbing work or water main repair
Disturbed pipes can release accumulated contaminants. Test 2-4 weeks after work is complete.
Regular Testing Schedule
- Private wells: Annually for bacteria and nitrates; every 3-5 years for comprehensive testing
- Municipal water (high-risk homes): Annually for lead if built pre-1986 or lead service line
- Municipal water (standard homes): Every 3-5 years or when moving to a new home
- After installing filtration: Test before and 6 months after to verify effectiveness
- Well water in agricultural areas: Test twice annually (spring and fall) for nitrates and pesticides
What to Test For: Contaminant Priority Guide
Comprehensive water testing for all contaminants costs $200-500+. Prioritize based on your situation to balance thoroughness with cost.
Tier 1: Essential Tests (Everyone Should Do)
Basic Water Quality Panel ($20-60)
- Bacteria (coliform/E. coli): Indicates fecal contamination
- Lead: Neurotoxin, especially dangerous for children
- pH: Affects corrosivity and taste
- Hardness: Affects appliances and soap effectiveness
- Total Dissolved Solids (TDS): General water quality indicator
Tier 2: Common Concerns ($60-150 total)
Add these if you have risk factors or live in affected areas:
- Nitrates/Nitrites: Critical for wells near agriculture or septic systems
- Arsenic: Common in Western U.S., New England, and Midwest
- Copper: Leaches from plumbing, especially acidic water
- Iron and manganese: Causes staining, common in well water
- Chlorine/chloramine: Affects taste, can form disinfection byproducts
- Fluoride: If concerned about levels (natural or added)
Tier 3: Specialized Tests ($100-300+ each)
Test for these if you have specific risk factors:
- PFAS (per- and polyfluoroalkyl substances): Near military bases, airports, fire training facilities, or industrial areas
- Pesticides/Herbicides: Near agricultural areas or golf courses
- VOCs (volatile organic compounds): Near gas stations, dry cleaners, industrial sites
- Chromium-6: Industrial contamination, especially in California
- Radionuclides (radon, uranium, radium): Certain geological areas, especially granite regions
- Perchlorate: Near military bases or rocket fuel facilities
Quick Selection Guide
Municipal water, modern home:
Basic panel (bacteria, lead, pH, hardness) - $20-60
Pre-1986 home:
Basic panel + copper - $30-80
Private well (rural):
Basic panel + nitrates + arsenic - $60-120
Private well (agricultural area):
Basic panel + nitrates + arsenic + pesticides - $150-250
Near contamination source:
Basic panel + PFAS + VOCs or relevant specialty test - $200-400
Pregnant or young children:
Comprehensive panel (all Tier 1 + Tier 2) - $150-300
Testing Options: DIY vs Professional
Option 1: DIY Test Kits
Best For: Quick screening, basic parameters
How they work: Test strips or chemical reactions that change color
Cost: $10-50
Speed: Immediate results (minutes)
Pros:
- Instant results
- Very affordable
- Easy to use, no training needed
- Good for monitoring trends
Cons:
- Less accurate than lab testing
- Limited contaminants (usually just pH, hardness, chlorine, iron, nitrates)
- Can't detect low levels
- Not legally defensible if you need to make claims
Popular Brands:
- First Alert WT1 Drinking Water Test Kit
- Watersafe Well Water Test Kit
- JNW Direct Water Test Strips
- Varify Water Quality Test Kit
Option 2: Mail-In Lab Test Kits
Best For: Accurate, certified results at reasonable cost
How they work: Collect sample at home, mail to certified lab
Cost: $50-300 depending on tests
Speed: 5-14 days for results
Pros:
- Accurate, certified lab analysis
- Wide range of contaminants available
- Convenient—collect at home
- Detailed reports with explanations
- Legally defensible results
Cons:
- Wait time for results
- More expensive than DIY strips
- Sample collection must be done correctly
Recommended Services:
- SimpleLab Tap Score: $180-350, comprehensive panels
- MyTapScore: $119-399, customizable by concern
- National Testing Labs: $149-299, various packages
- Tap Check: $75-300, specialty tests available
Option 3: Professional Lab Testing
Best For: Most accurate results, custom testing, legal purposes
How it works: Send sample directly to EPA-certified lab or hire professional to collect
Cost: $20-100 per test; $200-500+ for comprehensive panels
Speed: 3-10 days typically
Pros:
- Highest accuracy and precision
- EPA-certified labs
- Can customize exactly what you test
- Professional sample collection available
- Results accepted for legal/regulatory purposes
Cons:
- Most expensive option
- Requires coordinating with lab
- May need special sample bottles/preservation
How to Find:
- Contact your state health department for certified lab list
- EPA maintains database of certified labs by state
- Call EPA Safe Drinking Water Hotline: (800) 426-4791
Option 4: Free or Low-Cost Utility Testing
Best For: Basic screening if available
How to get: Contact your water utility
Cost: Often free, especially for lead testing
Pros:
- Free or very low cost
- Certified lab analysis
Cons:
- Not available everywhere
- May have long waiting lists
- Limited to basic tests
- Results can take weeks
How to Collect a Water Sample Correctly
Proper sample collection is CRITICAL for accurate results. Mistakes can lead to false positives or false negatives.
General Guidelines for All Tests
- Choose the right tap: Test from the tap you use most for drinking (usually kitchen sink). Test multiple taps if concerned about specific fixtures.
- Remove aerators/filters: Take off faucet aerators, screen filters, or any attachments before sampling (unless you want to test filtered water specifically).
- Clean the faucet: Wipe outside of faucet with clean cloth, but don't use soap or disinfectants on the spout.
- Use cold water only: Always collect from cold tap (hot water can have higher contamination).
- Label samples immediately: Mark sample bottle with date, time, location, and your name.
Specific Collection Methods by Contaminant
For Lead and Copper (First Draw Sample)
Critical for Lead Testing:
- Water must sit in pipes for at least 6 hours (overnight is ideal)
- Do NOT run water before collecting—no flushing, no washing hands, nothing
- Collect first water out of the tap directly into sample bottle
- Fill to line indicated (usually 250-500 mL)
- Optional: Also collect "flushed" sample after running water 2 minutes to compare
Why: Lead accumulates when water sits in pipes. First draw shows your maximum exposure.
For Bacteria (Coliform/E. coli)
Sterile Technique Required:
- Use ONLY the sterile bottle provided by lab (don't touch inside of bottle or cap)
- Run cold water for 2-3 minutes to flush service line
- Don't let bottle or cap touch faucet
- Fill to indicated line (leave some air space)
- Cap immediately
- Keep cool (refrigerate or use ice pack) and deliver to lab within 24-48 hours
Why: Bacteria can grow in sample or be contaminated during collection.
For Most Other Contaminants (Standard Sample)
- Run cold water for 30-60 seconds to flush service line
- Fill sample bottle to indicated line
- Cap tightly
- Store at room temperature (unless lab specifies otherwise)
- Ship or deliver according to kit instructions
Common Sampling Mistakes to Avoid
- Using hot water: Always use cold tap only
- Flushing before lead testing: Defeats the purpose; need first draw water
- Touching inside of sterile bottles: Contaminates bacteria samples
- Overfilling bottles: Can break during shipping or not leave room for expansion
- Using your own container: Labs provide specific bottles for a reason
- Waiting too long to ship: Some tests degrade quickly; follow timing instructions
- Not labeling samples: Lab can't process unlabeled samples
Understanding Your Test Results
Test results can be confusing with technical terms, units, and regulatory standards. Here's how to interpret what you receive.
Key Terms Explained
- MCL (Maximum Contaminant Level): Legal limit set by EPA; enforceable standard
- MCLG (Maximum Contaminant Level Goal): Health-based goal; not enforceable but represents ideal level
- AL (Action Level): Trigger for additional treatment (used for lead and copper)
- ND (Non-Detect): Below detection limit of test; doesn't mean zero
- ppb (parts per billion): Micrograms per liter (μg/L)
- ppm (parts per million): Milligrams per liter (mg/L)
- ppt (parts per trillion): Nanograms per liter (ng/L); used for PFAS
How to Read Your Report
Most lab reports will include:
- Detected level: The amount found in your sample
- Units: ppb, ppm, or ppt
- EPA MCL or guideline: For comparison
- Pass/Fail or interpretation: Lab's assessment
- Detection limit: Lowest level the test can measure
What Results Mean: Action Guide
Result: ND or well below MCL (less than 25%)
Action: Generally safe. Continue monitoring every 3-5 years or as recommended.
Result: 25-75% of MCL
Action: Within legal limits but worth monitoring. Consider filtration if vulnerable population. Test annually.
Result: 75-100% of MCL
Action: Approaching unsafe levels. Install filtration. Retest in 3-6 months. Contact utility to report.
Result: Above MCL or AL
Action: UNSAFE. Do not drink. Use bottled or filtered water immediately. Contact utility and health department. Install certified filtration. For bacteria, disinfect or boil until resolved.
Special Cases
Lead (Health Goal = 0, Action Level = 15 ppb)
- ND or <1 ppb: Excellent
- 1-5 ppb: Detectable but low; consider action if children present
- 5-15 ppb: Concerning; filtration recommended, especially for children
- > 15 ppb: Take immediate action; use bottled water; install NSF 53 filter
Bacteria (Coliform/E. coli)
- Present: UNSAFE. Disinfect water system; retest. Use bottled water or boil until resolved.
- Absent: Safe from bacterial contamination
PFAS (New MCLs: 4 ppt for PFOA/PFOS)
- ND: Excellent
- <4 ppt: Meets new standards but not zero; consider RO if pregnant/children
- 4-10 ppt: At or slightly above new MCL; filtration recommended
- > 10 ppt: Well above safe level; RO system strongly recommended
When to Retest
- After corrective action: Retest 1-2 weeks after installing filtration or treatment
- After high results: Retest in 1-3 months to confirm or investigate variability
- Seasonal changes: Some contaminants (like bacteria, nitrates) vary by season
- After system changes: New well pump, water main repair, plumbing work
Frequently Asked Questions
How much does water testing cost?
Basic DIY test strips: $10-50. Mail-in lab kits: $50-300. Professional comprehensive testing: $200-500+. Lead-only test: $15-40. PFAS test: $150-300. Many utilities offer free lead testing.
Are home test kits accurate?
DIY test strips are reasonably accurate for basic parameters (pH, hardness, chlorine) but less precise than lab testing. For health-critical contaminants like lead, PFAS, bacteria, or arsenic, use certified lab testing.
Can I use my refrigerator water for testing?
If you want to test your refrigerator filter's effectiveness, yes. However, to assess your home's plumbing, test from the tap before the filter. Test both to compare filtered vs unfiltered.
How long does testing take?
DIY kits: Immediate results. Mail-in kits: 5-14 days from when lab receives sample. Professional lab: 3-10 days typically. Rush testing available for extra fee in some cases.
Should I test filtered water or tap water?
Test unfiltered tap water first to know what you're dealing with. Then test filtered water to verify your filter is working. This helps you know if filtration is adequate.
My utility says water is safe, but should I still test?
Yes, especially if you have young children, are pregnant, or have a pre-1986 home. Utility testing measures water at the plant or in distribution, not at YOUR tap. Lead, copper, and other contaminants can leach from your home's plumbing.
How often should well owners test?
Annually for bacteria and nitrates at minimum. Every 3-5 years for comprehensive testing including metals, pH, and other parameters. More frequently if you notice changes in taste, smell, or appearance, or after heavy rain/flooding.
What if my test shows contamination above safe levels?
Stop drinking the water immediately. Use bottled water for drinking and cooking. Contact your water utility (municipal water) or health department (well water). Retest to confirm results. Install appropriate filtration certified to remove the specific contaminant.