Which US states and counties require a septic inspection before you sell? 116 rules in 22 states (2026 census)

Ask whether a septic inspection is required when you sell a house and the usual answer is "it depends on where you live." That is true, but it is not very useful. So we counted. Between three regional research passes and a final read of each official text on November 9, 2026 (six rules were added on November 13, 2026 from archived copies of the official texts), our census looked for every state, county, health-district and township rule in the 50 states that requires a septic inspection, evaluation or pump-out, or a well inspection or water test, because a property is sold or transferred. A rule counts only if we read it on an official source. EPA says more than one in five U.S. households depend on individual septic systems or small community cluster systems (EPA, About Septic Systems), so the answer matters to a lot of sellers.

Headline findings

• Most rules are local. 103 of the 116 rules were set by a county, health district, city or township. Only 13 apply statewide.
• Minnesota is the outlier. It has no state rule, yet 59 of the local rules in our census are Minnesota county rules (58 counties; Dakota County has separate septic and well rules). The state's own 2025 report says 142 of 185 local septic programs require an inspection at property transfer.
• Statewide septic rules are rarer than people think. 9 states have one. In Maine and New Hampshire it covers only shoreland or waterfront property, in Rhode Island it targets cesspools, and Washington's does not start until February 1, 2027.
• Three states go the other way. Florida and Wisconsin bar local point-of-sale rules, and Indiana voided local septic ordinances that differ from the state rule, so an old county page describing one may no longer be enforceable.
• Reports expire. Where the rule's own text says how long an inspection of an existing system stays valid, the windows run from 2 to 60 months.
• An official inspector list exists for most rules. For 94 of the 116 rules we recorded an official list or search of approved inspectors or licensed businesses; for most Minnesota counties that is the MPCA's statewide licensed-business search.

Where the local rules are

Local rules cluster in a handful of states. Minnesota leads with 59, followed by Michigan with 11, Colorado with 10 and Washington with 6. New York's rules are in Cattaraugus, Chautauqua and Seneca counties and the towns of Queensbury and St. Armand. Ohio's are in Summit, Carroll and Tuscarawas counties and the villages of Orange and Moreland Hills. Kansas has three (Johnson, Leavenworth and Cowley counties). California (Santa Cruz County), Indiana (St. Joseph County), Nebraska (Lancaster County, both well and septic) and South Dakota (Meade County) have one each in our census.

Who sets the rule changes what it covers. Many local rules are septic only, but some reach the well too. Macomb County, Michigan, and Cattaraugus and Chautauqua counties in New York, for example, look at both the water supply and the sewage system at transfer. In Michigan, several rules are township ordinances that a district health department carries out: the Health Department of Northwest Michigan says an evaluation is required if you sell property in Milton Township, Torch Lake Township, Elk Rapids Township or the Village of Elk Rapids (HDNW).

The chart is a count of rules, not of homes affected: a small rural county counts the same as King County, Washington. Statewide rules are counted separately, once each, however many counties they cover.

The statewide rules

One row per statewide rule; Rhode Island has two. The septic inspection hub compares the septic rules cell by cell (deadline, validity, who arranges it, what happens if the system fails); this table only shows what each one covers.

So a seller in Arizona, Iowa, Massachusetts, Delaware or New Mexico should expect a sale inspection almost anywhere in the state. A seller in Maine or New Hampshire needs to know whether the lot is in a shoreland or waterfront zone. A Rhode Island seller needs to know whether the house still has a cesspool. Our guides cover how to test well water for the four well-test states, and the lab finder lists state-certified labs.

Washington: a statewide rule that starts in 2027

Washington is the only state in our census whose statewide rule is adopted but not yet in force. Under WAC 246-272A-0270(1)(k), beginning February 1, 2027, the owner must obtain an inspection "by a third-party inspector authorized by the local health officer" at the time of property transfer, and submit the results on a form the local health officer approves (WAC 246-272A-0270). We count it now and flag it. Spokane Regional Health District and Yakima County already describe the 2027 state requirement on their own pages; we count it once, as the statewide rule. It is the only rule in the census with a later start date.

Several Washington counties, including King, Thurston, Pierce, Skagit, Island and Clallam, already require an inspection at transfer. The Washington page lists which local health jurisdictions already publish a transfer program and which do not yet. If you plan to sell in Washington in 2027, ask your local health jurisdiction which inspectors it authorizes and how long the review takes.

Three states whose law bars local sale rules

In many states a county can add a point-of-sale rule. In three, state law says it cannot, or voids the ones that existed, and no state rule takes their place. (Iowa's statute also preempts county rules, but replaces them with a statewide inspection.)

• Florida. Section 381.0065(4)(x) of the Florida Statutes says: "An inspection of a system may not be mandated by a governmental entity at the point of sale in a real estate transaction" (2026 Florida Statutes). A buyer can still order one.
• Wisconsin. Wis. Stat. 706.22 bars a local governmental unit from requiring an owner to take actions with respect to the property, which the statute defines to include having an inspection made, before, at or after a sale, refinancing or transfer of title, with exceptions set out in the statute (Wis. Stat. 706.22). Our census treats county septic pages that still describe a sale inspection (Manitowoc, Oneida and Vilas) as not in force.
• Indiana. The Indiana Department of Health says statutory changes (IC 16-19-3-27.8 and IC 16-41-25-7) voided local onsite sewage ordinances that vary from the state rule as of July 1, 2023 (IDOH, Office of Legal Affairs). The census treats the LaPorte and Blackford county sale rules as void. St. Joseph County's own page (in an archived copy from September 2026) still describes a narrower rule from July 2024: a septic inspection at transfer inside the St. Joseph Aquifer System and a water test before closing. We count it as the county publishes it; whether it fits the state law is for the county and the state to settle.

The practical point: in Florida and Wisconsin, and in most of Indiana, a sale inspection is a contract choice, not a legal step (St. Joseph County, Indiana, is the exception). If a county web page in Florida, Indiana or Wisconsin still says you need one, ask the county whether it is enforced before you pay for it.

Minnesota: no state rule, but most local programs require one

Minnesota has no state requirement, and it is still the state where a seller is most likely to face one. The Minnesota Pollution Control Agency's 2025 annual report on septic programs puts it directly: "There is currently no state-level requirement" for local governments to require compliance inspections at property transfer. Yet of the 185 local programs that reported in 2025, 142 said they require one: 59 counties, 53 cities, 27 townships and 3 other units of government (MPCA, 2025 SSTS Annual Report, April 2026, pp. 19–20). The same table shows 27 county programs that do not.

Our census counts 59 Minnesota county rules. For most of them we read the county's own ordinance or septic page. For the rest, the MPCA table is our only official source; those rules are counted, but their WaterListed pages stay out of search until we read the county's own text. Minnesota cities and townships are not listed one by one in our census, so a buyer in a city or township should ask that city or township directly. The Minnesota page lists every county we counted.

How long a report stays valid, and who may inspect

69 of the 116 rules state how long an inspection or certificate stays usable, in a form we could convert to months. The shortest are in Kansas: Leavenworth County's resale inspection is valid for 60 days and Cowley County's results for 90 days. Several others use about six months: New Mexico and New Hampshire use 180 days for statewide transfer evaluations, Skagit County, Washington, exempts a transfer when an inspection was done "within six months prior" (Skagit County Public Health), and Cattaraugus County, New York, accepts an inspection from the previous six months, with exceptions (Cattaraugus County Sanitary Code). For an existing system, the longest are five years: the Health Department of Northwest Michigan says its Time-of-Transfer evaluation "is good for five (5) years from the date of completion." Iowa's statute says an inspection "is valid for a period of two years for any ownership transfers during that period" (Iowa Code 455B.172).

The spread matters when a sale falls through and the house goes back on the market. A report that still works in Iowa can be stale in Skagit County. The hub has a worked example with one report across seven jurisdictions.

For 94 rules we recorded an official list or search: in Minnesota, the MPCA's search of licensed septic businesses (MPCA SSTS business search); in Iowa, the Department of Natural Resources' list of certified time-of-transfer inspectors (Iowa DNR). Under a sale rule, a report from someone not on the list may not count. We do not name inspectors; use the official list linked on each rule page.

Only 20 rules state a fee amount in the text we read. Dated county fees, and what pushes a private inspector's quote up, are in our septic inspection cost guide.

What "no rule found" means

For 26 states we found no state or local point-of-sale rule that we could confirm on an official source. Read that carefully. It means our searches, at least one targeted search per state, did not turn up a counted rule. It does not mean a seller there never needs an inspection. Three reasons:

• Some rules sit behind sites that blocked us. Where an archived copy of the official page exists, we read that instead and say so; that is how Arizona's statewide rule and the Santa Cruz (CA), Lancaster (NE), St. Joseph (IN), Leavenworth and Cowley (KS) county rules were counted. County rules in Washington (Whatcom, Kitsap, Mason) and elsewhere are still in the queue.
• Thousands of local codes were not checked one by one. Pennsylvania's township ordinances, many New Jersey and Connecticut municipal codes, and many of Ohio's health districts and Michigan's health departments were not checked.
• A disclosure is not an inspection. Connecticut and Vermont require that a buyer of a home with a well get the state's well-testing information, not a test or a septic inspection (see our well-testing study), so they are in this group.

If your state is in this group, call the county health department and ask two questions: is there a county or town rule at transfer, and does it cover the septic system, the well, or both.

Method and limits

The census covered the 50 states and the District of Columbia in three regional research passes, merged on November 9, 2026. We counted a rule when it requires a septic inspection, evaluation or pump-out, or a well inspection or water test, because a property is sold or transferred, and when its official text (state code, administrative code, county ordinance or health-department page) or an official state roster was read on November 9, 2026 (for six rules added on November 13, 2026, an Internet Archive copy of the official URL). Where the live official site blocked us, we read an Internet Archive copy of the official URL; the census file records which source was read for each rule. Adopted rules with a later start date are counted and flagged.

• "No rule found" is not "no rule." See the section above.
• Some Minnesota counties are roster-only. They count on the strength of the MPCA 2025 report table. Their pages are not indexed until the county text is read.
• Not counted: rules seen only in secondary sources, rules behind blocked official sites with no readable archived official copy, proposed rules, repealed rules, voluntary programs and rules voided by state law. Where an official county page and the state roster disagreed, the county was not counted. All of these stay in the census file with a reason.
• One count per rule. A statewide rule counts once, however many counties it covers. A county with both a septic and a well rule in one program counts once.
• Lender rules are not counted. FHA, VA and USDA loans have their own septic and well conditions, but a lender is not a jurisdiction. The hub quotes what each agency's current handbook says, and our FHA, VA and USDA well water test guide covers the water side.
• Statutes, not guidance pages. This census reads rule texts. Our earlier study of well testing at home sale classified what state agency guidance pages say. It missed Maryland's law at first and was corrected on November 10, 2026, so both now list the same well-test laws in Maryland, Oregon and Rhode Island. New Jersey's law is here but outside that study, which covers only states with a lab list on WaterListed.
• Pages change. Every rule page shows the date we last read the official text. A rule adopted after November 13, 2026 is not here.

Getting the data

Every rule in this study has its own page on WaterListed, with the official text linked: start from the septic inspection hub and the state pages. We do not publish the full table as a download. Journalists and researchers who need the rule-by-rule table can request it here: say who you are, where the work will appear and which data you need, and we will reply.

Blank fields on a rule page mean the official text we read did not say, not that the answer is "none."

Questions people ask