The EPA recommends testing your well water at least once per year[1]. Most well owners don't.
That is a gamble. Well water quality can change without warning. Here is the testing schedule that keeps your family safe.
Quick Answer
Test for bacteriaColiform BacteriaA group of bacteria used as indicators of potential contamination. Total coliform presence suggests a pathway for pathogens to enter your well.EPA MCL: 0 (no coliform should be present)Learn more → (contamination indicators) and nitratesNitratesCompounds that enter groundwater from fertilizers, septic systems, and animal waste. Especially dangerous for infants under 6 months (blue baby syndrome).EPA MCL: 10 mg/L (ppm)Learn more → (fertilizer compounds) every year. Test everything else every 3–5 years. Test immediately after flooding, well repair, a new baby, or any change in taste, smell, or appearance.
Annual Testing Schedule
| What to Test | How Often | Why | Cost |
|---|---|---|---|
| BacteriaColiform BacteriaA group of bacteria used as indicators of potential contamination. Total coliform presence suggests a pathway for pathogens to enter your well.EPA MCL: 0 (no coliform should be present)Learn more → (coliform + E. coli) | Every year | No disinfection = no safety net | $15–$30 |
| NitratesNitratesCompounds that enter groundwater from fertilizers, septic systems, and animal waste. Especially dangerous for infants under 6 months (blue baby syndrome).EPA MCL: 10 mg/L (ppm)Learn more → | Every year | Levels can spike seasonally | $15–$25 |
| pH | Every 3 years | Slow changes; affects corrosion | $10–$20 |
| IronIronA naturally occurring mineral found in groundwater. Iron causes orange/rust staining on fixtures and laundry and gives water a metallic taste.EPA Secondary MCL: 0.3 mg/L (ppm)Learn more → + ManganeseManganeseA mineral that causes black or brown staining and can affect the taste of water. Often found alongside iron in well water.EPA Secondary MCL: 0.05 mg/L (ppm). EPA Health Advisory: 0.3 mg/LLearn more → | Every 3 years | Gradual changes; affects staining | $20–$40 |
| HardnessHardness (Calcium Carbonate)The concentration of dissolved calcium and magnesium in water. Hard water causes scale buildup in pipes, water heaters, and fixtures.No EPA standard. Soft: <1 gpg. Moderate: 1-7 gpg. Hard: 7-10.5 gpg. Very Hard: >10.5 gpg.Learn more → + TDSTDS (Total Dissolved Solids)The total amount of dissolved minerals, salts, and metals in water. A general indicator of water quality, though not all dissolved solids are harmful.EPA Secondary MCL: 500 mg/LLearn more → | Every 3–5 years | Stable unless geology changes | $15–$30 |
| ArsenicArsenicA toxic element found naturally in bedrock that dissolves into groundwater. Odorless and tasteless, making testing the only way to detect it.EPA MCL: 10 ppb (0.01 mg/L)Learn more → | Every 3–5 years | Geology-dependent; test if in risk area | $20–$40 |
| LeadLeadA toxic metal that typically enters water from corroded plumbing, solder, or fixtures rather than the well itself. No safe level of lead exposure.EPA Action Level: 15 ppb (0.015 mg/L)Learn more → | Once (then if pH changes) | From plumbing, not the well itself | $20–$30 |
Total annual cost for the basics: $30–$55[2].
Already have your test results? Get a plain-English diagnosis.
Analyze My Water TestWhen to Test Immediately
Do not wait for your annual test if any of these happen[1]:
- Flooding or heavy rain near your well. Surface water can wash bacteria in.
- Well repair or pump replacement. Opening the well introduces contamination risk.
- New baby in the home. Test for nitrates, bacteria, lead, and fluoride before using well water for formula.
- Unexplained illness in your household — especially gastrointestinal symptoms.
- Change in taste, smell, or appearance. New staining, cloudiness, or odor signals something changed.
- Nearby land use changes. New farm, construction, or septic installation within 200 feet.
- You just bought the home. Get a full baseline test.
Lab Test vs DIY Test Strips
| Certified Lab Test | DIY Test Strips | |
|---|---|---|
| Accuracy | High (ppb-level precision) | Low (rough estimate only) |
| Best for | Health contaminants, official results | Quick pH/hardness check |
| Cost | $30–$200 per panel | $10–$30 per kit |
| Use for health decisions? | Yes | No |
Rule of thumb: Use DIY strips for hardness and pH checks between lab tests. Use a certified lab for bacteria, nitrates, arsenic, lead, and any health-related testing[5].
How to Find a Certified Lab
- Contact your state health department. Most maintain a list of certified labs.
- Search "certified drinking water lab" + your state on the EPA website.
- Use a mail-in service like Tap Score. They handle sample collection, shipping, and reporting.
What to Do Next
Haven't tested in over a year? Order a bacteria + nitrates test now. Cost: about $40.
Haven't tested in 3+ years? Get a full panel. Add arsenic if you are in a risk area.
Just got results? Read our How to Read a Water Test Report guide, or enter your numbers in the Water Test Interpreter.
Frequently Asked Questions
How often should I test?
Bacteria and nitrates: every year. Full panel: every 3–5 years. Immediately after flooding, well repair, or changes in taste/smell[1].
How much does testing cost?
Bacteria + nitrates: $30–$50. Full panel: $80–$200. Mail-in services (Tap Score): $100–$400[2].
Can I use DIY test strips?
For pH and hardness: yes. For health contaminants (bacteria, nitrates, arsenic, lead): always use a certified lab[5].
References
- U.S. EPA. "Private Drinking Water Wells: When to Test." 2024. https://www.epa.gov/privatewells
- CDC. "Testing Your Private Well Water." 2024. https://www.cdc.gov/healthywater/drinking/private
- U.S. EPA. "Safe Drinking Water Act: MCLs." 2024. https://www.epa.gov/sdwa
- National Ground Water Association. "Well Water Testing Schedule." 2024. https://www.ngwa.org
- Penn State Extension. "Water Testing for Private Wells." 2023.
- Virginia Cooperative Extension. "When and How to Test Your Well Water." 2022.