Why test water on a farm?
Farm water serves people, animals and crops. A problem in the water can cause illness in a household, poor animal health or contaminated produce. Private wells are usually the owner's responsibility, because public systems are tested by the supplier and private ones often are not.
Testing also gives you a baseline. If conditions change later, you will know what was normal for your site.
Livestock water matters as much as household water. Animals drink a lot, and poor water can cut feed intake, slow growth or carry disease. Ask your veterinarian whether any animal-specific tests are worth doing.
What should I test for?
The right tests depend on your area, your water source and your use. Common starting points include bacteria, nitrate, pH and hardness, and your local situation may call for others, such as metals, salts or contaminants linked to nearby land use.
Ask your county health department or extension office which tests are recommended in your area, and ask which are needed for drinking water, for livestock and for irrigating food crops. Testing needs differ for each use.
Surface water such as ponds and streams changes with rain, season and what happens upstream, so one test is only a snapshot. If you irrigate food crops from surface water, ask your extension office about food safety guidance for irrigation water.
- Bacteria, as an indicator of contamination
- Nitrate, often linked to fertilizer, manure or septic
- pH and hardness for plumbing and equipment
- Area-specific items your local office recommends
Where do I send samples?
Use a laboratory certified by your state for drinking water testing. Your health department or extension office can give you a list. Avoid mail-order kits with unclear lab credentials when the result matters for health.
Call the lab before you collect a sample. Ask for the right bottles and the exact instructions for collection, storage and delivery, since many tests have strict time limits.
Ask what the lab charges before you commit, and whether they can group tests into a package. Cost categories include the tests, the bottles, shipping or travel, and any follow-up testing.
How do I collect a good sample?
Follow the lab's directions word for word. In general, clean hands, clean sampling point and sterile containers matter for bacteria tests, and the instructions may call for running the tap for a set time first. Do not rinse sterile bottles.
Label the bottles, note the date and time and the sample location, and deliver them by the deadline. A poor sample gives a misleading result, so take your time.
Sample after heavy rain or flooding as well as in dry periods when you can, because conditions change.
What do the results mean?
The lab report lists results next to standards or guidelines. Ask the lab or your health department to help interpret them, especially if something is flagged. Do not drink or give animals water that fails a bacteria test until you have advice.
If a result is concerning, retest to confirm and ask a qualified professional what to do. Treatment, repair and disinfection of a well should follow local guidance and may require licensed help.
Do not try to treat a bacteria problem with improvised steps. Ask your health department what to do and whether a licensed professional should disinfect and retest the system.
- Record the lab name and date
- Do not drink or water animals until you have advice
- Retest to confirm a surprising result
How often should I test, and what should I keep?
Many health agencies suggest testing private wells at least once a year for key items, and after events such as flooding, repairs, changes in taste, smell or color, or if someone in the home is pregnant or has a baby. Ask your local office for its recommendation.
Keep every report in a folder with the date and sample location. Trends over time tell you more than any one result, and the records will help if you sell the property.
If you rent land or buy a property, ask for past test results, and plan to run a fresh test before you drink the water or water animals.
- Annual tests for key items
- After floods or repairs
- When taste, smell or color changes
- When a pregnant person or infant is in the home
Key takeaways
- Test private water sources, because no one else will do it for you.
- Ask your local health or extension office which tests fit your area and your use.
- Use a certified lab and follow collection instructions exactly.
- Retest regularly and after floods, repairs or changes in the water.
Sources and further reading
Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.