Which states require well water testing when you sell a home? Only 3 of the 45 we checked

Buy a house on a private well and you might assume someone checked the water before closing. In most of the country, nobody had to. EPA puts it plainly: "Private well owners are responsible for delivering safe drinking water to their households," and the quality and safety of drinking water from private wells "are not regulated by the Federal Government under the Safe Drinking Water Act nor by most state governments and laws." We sorted what each state agency in our dataset says about testing a well at a home sale into six categories.

What the agency pages say, in six categories

Each state sits in the strongest category its official pages support, read conservatively: a lender that "may" require a test is not a state law (see method). In 12 jurisdictions the strongest finding points to a requirement: a test law, a disclosure law, or a statement that a lender or local government may require a test.

The states that require a test

Oregon

Oregon's Domestic Well Testing Act (ORS 448.271) "applies to the sale or exchange of real estate with a domestic well," according to the Oregon Health Authority (OHA). The seller must have the water tested for arsenic, nitrate and total coliform bacteria by an accredited lab. Within 90 days, the seller or their representative sends the results to the buyer, and the Real Estate Transaction (RET) form plus the results to OHA. Oregon's rules (OAR 333-061-0325) add that the test happens upon accepting an offer, that it cannot be waived even if the buyer agrees to skip it, and that results tied to the sale are valid for one year. Failing to test does not invalidate the sale documents. OHA lists properties with spring wells or irrigation-only wells as exempt, and the rules add that capped domestic wells on unimproved lots do not need testing (OAR 333-061-0325(9)).

The required panel is three tests: arsenic, nitrate and total coliform bacteria. Lead, PFAS and uranium are not on it. A buyer can still ask for them.

Rhode Island

Rhode Island's regulation on private drinking water systems says all wells used for drinking water "shall be tested ... Prior to the sale or transfer (as defined herein) of ownership of real property" (216-RICR-50-05-2, section 2.12.1). The same section requires a test before a certificate of occupancy and when a new well is installed. The Rhode Island Department of Health (RIDOH) says the regulation sets a minimum list of tests and that its buying-a-home tip sheet explains which tests are needed and who is responsible. RIDOH also notes that PFAS is not currently on the required list; buyers can order it.

Maryland

Maryland's rule is newer and works differently. Real Property § 10-713, added by the Private Well Safety Act of 2023 (Chapter 587) and in force since October 1, 2024, says a contract to sell property with a private or domestic water supply well "shall include a provision requiring, as a condition of the sale, that the purchaser ensure that water quality testing of the well be conducted." Settlement may not take place until the seller and the buyer have each received and reviewed the results, and both certify that in writing at settlement. Results stay valid for 3 years.

Two points set it apart from Oregon. The buyer, not the seller, makes sure the test happens, and the buyer "may waive in writing" the testing requirement. The law defines the test as sampling by a State-approved water sampler and analysis by a State-approved laboratory, covering at least bacteria, nitrate and turbidity. The Maryland Department of the Environment also recommends a certified sampler for real estate testing. Our Maryland page lists the state's certified labs.

Connecticut and Vermont: information, not a test

Connecticut and Vermont are the two states in our data where the law makes sure the buyer gets well-testing information without requiring a test. Under Connecticut General Statutes § 19a-37, before a property with a private well is sold or rented, the buyer or tenant must be told that the Department of Public Health's well-testing material is available and must be given a copy. That material recommends testing. It does not require it, so we count Connecticut as a disclosure state. Buyers there decide whether to test; our Connecticut page lists the state's certified labs.

Vermont's law, 27 V.S.A. § 616, applies to sale contracts signed on or after January 1, 2013 for property whose drinking water is not served by a public water system. Within 72 hours of signing, the seller must give the buyer Department of Health material on "the potential health effects of the consumption of contaminated groundwater" and "the availability of test kits provided by the Department of Health." Missing it does not affect title; the penalty is a civil fine of $25 to $250. The Health Department's real estate page lists the hand-over of its Well Water Testing: A Home Buyer's Guide as "Required by law," while its well page says "you are not required to test your water when you sell your home." Minnesota's statute only makes sellers disclose the wells themselves, so it is not counted here.

Where an official page says there is no state rule

In 7 jurisdictions (Minnesota, Wisconsin, Pennsylvania, Massachusetts, Tennessee, Louisiana, Nebraska), an official source says outright that state law does not require a test. Most point to someone else who may. MassDEP names your mortgage lender or local Board of Health; Louisiana's health department says lenders often require some type of testing; Tennessee's TDEC tells buyers to ask the lender which tests it needs. Minnesota's Department of Health says the state "does not require testing private well water at the time of property transfer," though lenders may and Dakota County does. Wisconsin's DNR says "State law does not require a well inspection or water testing for a property transfer."

Where lenders or local governments may require one

In 7 jurisdictions (Washington, Georgia, Oklahoma, Nevada, Kansas, Arizona, Montana), the official pages we read say a test may be required, but by a lender or a local government rather than by state law. Washington's Department of Health says your county health or planning department, or your lender, may require a water sample when a home is sold. Oklahoma's DEQ says it does not regulate private wells, but many lenders require a test before closing, most often for total coliform/E. coli, lead and nitrate/nitrite. It adds that some lenders want the test done no more than 30 days before closing.

Nevada needs a word of explanation. NDEP says that when testing is "a condition required by a lending institution for the transfer of real property," it "must be performed by a laboratory certified by the State of Nevada," and cites NRS 455A.863. That is a rule about who tests, not a rule that a test must happen, so we count Nevada with the lender-driven states.

Where testing is recommended, with no requirement stated

In 5 jurisdictions (Missouri, Alabama, Michigan, South Carolina, New Mexico), the state or its extension service recommends or explains testing at a sale without saying whether anything is required. Missouri and South Carolina steer sellers away from the state's own testing: Missouri's health department offers it "as a public health service" but not for real estate transactions. Use a certified commercial lab from the lab finder.

Where we found nothing

For 21 jurisdictions (Maine, Ohio, Virginia, New York, California, Illinois, Iowa, Florida, Texas, Wyoming, Hawaii, Mississippi, South Dakota, Colorado, West Virginia, North Carolina, Alaska, Puerto Rico, Indiana, Kentucky, Idaho), the official pages in our fact-checked state guidance have no item about a home sale. It is the group most easily misread: "none found" means the pages we read did not cover a sale. It does not mean the state has no rule.

State by state

Each row comes from our by-state record: category, a summary of each official item credited to its agency, the source and the date our guidance was checked.

New Jersey is not in this dataset

New Jersey has a Private Well Testing Act (N.J.S.A. 58:12A-26 et seq.), according to the New Jersey Department of Environmental Protection. We read that from the Internet Archive copy of the DEP's Private Well Testing Act page captured on September 17, 2026, because the live page blocks automated access. New Jersey has no live lab list on WaterListed yet, so we did not review its rules for this dataset and do not summarize them here. Buying or selling in New Jersey, read the DEP's page or ask the DEP. For the same reason this is not a 50-state map: states without a lab list on our site were not assessed.

Local rules can apply where the state has none

Counties can set rules where the state has none, or add their own to a state rule. Three examples from county pages:

• Santa Cruz County, California. "Beginning September 1, 2025, when Rural Real Estate is transferred," the water system "must be tested to confirm it has acceptable yield ... and water quality," and the seller gives a disclosure form with the results to the buyer and the county (County Code Section 7.73.075; Internet Archive capture of July 13, 2026). Our well flow test guide covers the pass lines.
• Baltimore County, Maryland. The county keeps a "Waiver of Chemical Quality Prior to Conveyance" for buyers who agree to purchase a property "without a well meeting the water quality requirements," and a separate yield waiver (forms page, Internet Archive capture of September 11, 2025). These county forms sit alongside the state law described above. See the well flow test guide.
• King County, Washington. Here the sale rule is about the septic system, not the water: properties with a septic system "must have their system inspected by a certified on-site system maintainer before the transfer of title," says Public Health – Seattle & King County. Our well and septic inspection guide explains how that fits with a well test.

Minnesota's Department of Health names a fourth: a Dakota County ordinance that requires a well test at transfer. If your state is in the "none found" group, the county health department is the next call.

Lenders set their own rules

For many buyers, the test that happens is the one the lender asks for. State agency and extension pages say so, including Louisiana, Oklahoma, Kansas, Massachusetts, Nebraska and Tennessee. FHA, VA and USDA loans have their own well rules, which change often; our guide to FHA, VA and USDA well water test requirements keeps them dated. A lender requirement is a loan condition, not state law.

Timing is the trap. Oklahoma's DEQ notes that if total coliform is found, the well has to be disinfected and retested, and "This process alone can take several weeks." Nebraska's state lab advises allowing at least a week, and preferably two, for results. Order the test early in the contract period.

If you are buying or selling a home with a well

1. Find your state in the table. In Oregon the seller's test is required, and in Rhode Island the regulation requires a test before the sale or transfer. In Maryland the contract must make a test a condition of the sale, arranged by the buyer unless the buyer waives it in writing. Follow the sources in that row.
2. Ask the county health department whether a local rule applies, and ask the lender which tests it needs and how recent they must be.
3. Where no one requires a test, consider making one a contract contingency. Our which-tests checklist helps you choose beyond the basic bacteria and nitrate panel.
4. Use a state-certified lab. The finder shows every lab on your state's list. Bacteria samples have to reach the lab quickly, so read how to collect a well water sample and the testing-deserts study on how far some owners are from a lab.
5. Read the report against your state's guidance; federal drinking-water limits apply to public water systems, not private wells.

For anything with legal weight, such as who pays or what happens if a test fails, ask a real estate attorney or the state agency.

Method

We started from WaterListed's fact-checked state guidance: the official health, environment and extension pages we read for each of the 45 jurisdictions with a lab list on this site, checked between November 1 and 4, 2026. We did no new research for the categories, with one exception: on November 10, 2026 we added Maryland's statute after finding it while researching our septic and well rules at sale study. Each guidance item about a home sale was put in one of the six categories in the chart, and each state takes the strongest category any of its items supports, in the chart's order (law requires a test first, none found last). "Law requires a test" is used only where an official item says state law or regulation requires a test at sale or transfer; a law that only requires handing over information is a disclosure. Lender and FHA/HUD requirements are not state law and count as "lenders or local governments may require."

The reading is deliberately conservative. Nevada's rule on who must test when a lender requires a test is counted as lender-driven. The disclosure category counts only a law that gives the buyer well-testing information (Connecticut, Vermont); Minnesota's well-disclosure statute, which covers the existence, status and location of wells, stays in "no state requirement," with the statute noted in the reason. Illinois' items concern new and repaired wells, so Illinois is "none found." The classification script checks a guard phrase in every item it relies on and stops if a state's guidance changes, so a state cannot be silently mislabeled.

Limits

• "None found" does not prove no rule exists. It means the official pages already in our guidance said nothing about a sale. Other official pages, or a statute we did not read, can say more.
• Not a 50-state map. Only the 45 jurisdictions with a live lab list on WaterListed are covered. New Jersey, which has a Private Well Testing Act, is not among them.
• Oregon's rental law is not in force yet. HB 3525 (2025) addresses landlord testing of domestic wells in groundwater management areas. OHA said no proposed rules were out for public comment as of November 2, 2026; its advisory committee minutes (August 20, 2026) plan a comment period from mid-November 2026 and a January 1, 2027 start.
• Local and lender rules are not counted as state law, and we have not surveyed counties. The county examples are illustrations, not a census.
• Agency pages can miss a statute. Maryland's agency page did not mention the state's 2023 law, so the first version of this study missed it. Other states may have laws that their agency pages do not mention.
• Pages change. Each row shows when our guidance was last checked. A rule adopted after that date is not here.

Getting the data

Behind the table above is one by-state record: one row per jurisdiction with the category, the reason, the full text of every official item, the source titles and URLs, and the date our guidance was checked. We do not publish it as a download. Journalists and researchers can request the data here: say who you are, where the work will appear and which data you need, and we will reply.

Questions people ask