Quick answer: Before you close on a house with a private well, get (1) a water test from a state-certified lab for at least coliform bacteria and nitrate, plus local contaminants of concern; (2) an inspection of the wellhead, pump and pressure tank by a qualified well or pump professional; (3) a flow (yield) test to confirm the well produces enough water; and (4) the well log and maintenance records. Make the purchase contingent on acceptable results.
1. Get the documents
- Well log (driller’s report). It shows the well’s depth, casing depth and diameter, water level and the yield when it was drilled. Many states keep these online or on request; the driller may also have it.
- Past water test results. A history of clean tests is reassuring; a gap is worth asking about.
- Maintenance and repair records for the pump, pressure tank and any treatment equipment, including their ages.
- Septic system records, since the septic system and well sit on the same lot.
2. Test the water
At a minimum, test for:
- Total coliform bacteria (and E. coli)
- Nitrate
The CDC’s annual list for well owners adds pH and total dissolved solids. Ask the local health department about contaminants common in your area, such as arsenic, radon or specific farm chemicals, and test for those too. See our full well water testing guide.
Tips:
- Use a state-certified lab and have the sample taken by the inspector or lab, not by the seller.
- If there’s treatment equipment, ask for a sample from before the treatment too, so you know what the equipment is dealing with.
- Some states require a water test when a home with a well is sold (Oregon, for example, requires sellers to test for bacteria and nitrate). Check your state’s rules.
3. Inspect the well and equipment
Have a licensed well or pump contractor check:
| Item | What to look for |
|---|---|
| Well cap | Tight, undamaged, with a screened vent. No missing bolts or cracks. |
| Casing height | Oregon State University notes a well whose top extends at least one foot above ground with a proper cap is a good sign. Buried or pit wells are more vulnerable. |
| Surroundings | Ground slopes away from the well; no standing water, fuel tanks, chemicals or animal pens nearby. |
| Distance to septic | Meets your state’s minimum setback. |
| Pump | Age, how it runs, amperage and cycling. |
| Pressure tank | Correct air charge; no rust, leaks or waterlogging. |
| Pressure switch | Contacts and settings; see pressure switch settings. |
| Treatment equipment | Working, maintained, and matched to the water problems. |
4. Ask for a flow (yield) test
A flow test checks whether the well can keep up with a household’s demand. OSU notes that 5 gallons per minute is generally accepted as adequate for a home. If the house is being sold in a wet season, a well’s yield can look better than it will in late summer; ask about dry-season performance.
5. Questions to ask the seller
- How old is the well, and who drilled it?
- Has the well ever run dry or produced less water?
- Have there been water quality problems: smell, stains, bacteria?
- When were the pump and pressure tank last replaced?
- Is there any water treatment equipment, and why was it installed?
- Have neighbors had well problems?
Red flags
- A positive bacteria test that keeps coming back after shocking.
- Nitrate near or above 10 mg/L, especially if you have or plan to have a baby. See nitrate in well water.
- Low yield or a history of running dry.
- A well cap below ground level or in a pit.
- No well log and no records at all.
None of these automatically kills a deal, but each can cost money to fix. Get estimates and negotiate before you close.
Frequently asked questions
Should I get a well inspection when buying a house?
Yes. A standard home inspection usually does not include a detailed well inspection or a lab water test. Order them separately.
Who pays for the well inspection?
It’s negotiable and varies by market. Buyers usually order it so the results are independent.
How long does a well water test take?
Bacteria results often come back within a few days; a full panel can take longer. Build that time into your contingency period.
What is a good flow rate for a residential well?
Around 5 gallons per minute is generally considered adequate for a household.
Related guides
- Well water testing: what to test for and how often
- Coliform bacteria in well water
- How to shock a well with bleach
Sources
- Oregon State University Well Water Program – Purchasing a Home with a Well
- CDC – Guidelines for Testing Well Water
- U.S. EPA – Protect Your Home’s Water
This guide is for general information and is not legal or real estate advice. Requirements for well testing at sale vary by state.
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