Well Water Testing When Buying a Home

Well water testing is one of the most important — and most overlooked — parts of buying a rural home. A failed well test can cost tens of thousands of dollars to remediate. Here is what to test for, who pays, and how to use results in your negotiation.

Minimum Tests for Any Home Purchase

Every rural home purchase should include at minimum:

• Total coliform bacteria — required by most lenders for rural properties
• E. coli — required by most lenders
• Nitrates — required by most lenders; especially important if infants may be present
• pH — determines corrosion risk to plumbing
• Hardness — affects appliances and plumbing

Additional Tests Based on Location

• Arsenic — if in a high-risk region (West, New England, upper Midwest)
• Radon — if in granite bedrock region (New England, Appalachians)
• Lead — if home was built before 1986
• Iron and manganese — if you see staining or discoloration
• VOCs — if near industrial sites, gas stations, or dry cleaners

Who Pays for Well Water Testing?

This is negotiable and varies by market. In many rural markets, the buyer pays for the water test as part of their due diligence inspection costs. In markets where well testing is standard, sellers sometimes provide a recent test result. If the seller provides a test, verify it was done by a certified lab and is less than 90 days old.

Using Test Results in Negotiation

If tests reveal problems:

• Bacteria: Request seller-paid shock chlorination and retest before closing. If bacteria persist, request a price reduction for well remediation.
• High nitrates: Request a reverse osmosis system be installed at seller's expense, or a price reduction equal to the cost.
• High iron or manganese: Cosmetic issue — negotiate a price reduction for treatment system cost.
• Arsenic above MCL: Request RO installation or significant price reduction — this is a serious, ongoing issue.
• Low pH with elevated lead: Request plumbing inspection and remediation or price reduction.

Hire a Certified Lab, Not a Water Treatment Company

Some water treatment companies offer "free water tests" — these are sales tools, not objective assessments. Use a state-certified independent laboratory for any test that will drive a purchase decision. Your state health department provides a list of certified labs.

Frequently Asked Questions

What well water tests are required when buying a rural home?

At minimum: total coliform bacteria, E. coli, and nitrates, which most lenders require for rural properties, plus pH (corrosion risk) and hardness (affects appliances and plumbing). Additional tests like arsenic, radon, lead, or iron may apply depending on the home's region and age.

Who typically pays for the well water test during a home purchase?

It's negotiable and varies by market. In many rural markets the buyer covers the water test as part of due diligence, while in markets where testing is standard, sellers sometimes provide a recent result. If the seller provides one, confirm it came from a certified lab and is less than 90 days old.

What can I negotiate if the well test comes back with problems?

It depends on the issue: for bacteria, request seller-paid shock chlorination and a retest before closing; for high nitrates, ask for a reverse osmosis system or an equivalent price reduction; for arsenic above the MCL, request RO installation or a significant price reduction, since it's a serious ongoing issue.

Should I use a water treatment company's free test when buying a home?

No. Free water tests from treatment companies are sales tools, not objective assessments. Use a state-certified independent laboratory for any test that will influence a purchase decision — your state health department maintains a list of certified labs.

When should I order the well water test during the home buying process?

As early as possible. Lab results take 3–10 business days, so order your water test at the same time as your home inspection to make sure you have results back before your inspection contingency deadline.