Septic system inspection at property sale: which states require it
For each US state whose statute, code or environmental agency states a position: whether a septic (onsite sewage) system must be inspected when the property is sold or the deed transfers, who must obtain it, and any exemptions. The sibling of well-water-testing-at-property-transfer, and it carries a date that will make today's answers wrong: Washington's WAC 246-272A-0270 requires, verbatim, 'Beginning February 1, 2027, obtain an inspection ... by a third-party inspector authorized by the local health officer' at the time of property transfer — so every page and model answering 'no statewide requirement in Washington' becomes wrong on that date. Iowa Code 455B.172 already requires a certified time-of-transfer inspection before deed transfer; Massachusetts Title 5 is the flagship law (mass.gov currently 403s our fetcher — use the 310 CMR 15.301 regulation text). Most states have no statewide rule and the requirement is county-level or the lender's; those statements are records too. Answers 'do I need a septic inspection to sell my house in [state]', 'what is a time of transfer inspection', and 'when does Washington's septic inspection rule start'. States whose authority states nothing get no record.
The data
| State | Inspection required at sale? | Exemptions | Authority | Who obtains / pays |
|---|---|---|---|---|
| Delaware | For all properties utilizing an OWTDS that are sold or otherwise transferred to other ownership, the persons must have the system pumped out and inspected by a Class F and Class H licensee, respectively, prior to completion of the sale | If an inspection has occurred within the previous 36 months and the property owner can provide proof of the pump out and inspection and the system is not a cesspool or seepage pit, then the inspections referred to in Section 3.31.13 will suffice | 7 Del. Admin. Code § 7101-3.0 | |
| Iowa | requires that every home or building served by a private sewage disposal system (PSDS) have that system inspected prior to the sale or deed transfer of the home or building. All inspections must be conducted by an inspector that has been certified by the Iowa DNR | Iowa Code 455B.172 | ||
| Massachusetts | a system shall be inspected at or within two years prior to the time of transfer of title to the facility served by the system | 310 CMR 15.301 | ||
| Minnesota | Before signing an agreement to sell or transfer real property, the seller or transferor must disclose in writing to the buyer or transferee information on how sewage generated at the property is managed | Sec. 115.55 MN Statutes | the seller or transferor | |
| New Hampshire | Prior to the transfer of any developed waterfront property using a septic system, where any portion of the septic system is within 250 feet of the reference line as defined in RSA 483-B:4, XVII, the buyer of the property shall, at the buyer's expense, engage a New Hampshire licensed septic system evaluator to conduct a septic system evaluation | the buyer may accept an evaluation prepared for the seller of the property if the evaluation was completed within 180 days of the date of property transfer | Section 485-A:39 | the buyer of the property shall, at the buyer's expense, engage a New Hampshire licensed septic system evaluator |
| Rhode Island | Any cesspool found to be serving a building or use subject to sale or transfer shall be removed and replaced with an OWTS or the building served by the cesspool shall be connected to a public sewer system within twelve (12) months of the date of sale or transfer | R.I. Gen. Laws § 23-19.15-12 | ||
| Washington | Beginning February 1, 2027, obtain an inspection, as required in WAC 246-272A-0260 (5), by a third-party inspector authorized by the local health officer | The local health officer may: (A) Remove the requirement for an inspection at the time of property transfer if the local health jurisdiction has evidence that the OSS is in compliance with (e) of this subsection and the OSS was inspected by a third-party inspector authorized by the local health officer | WAC 246-272A-0270 |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 7 sources this dataset was assembled from.
- law.cornell.eduhttps://www.law.cornell.edu/regulations/delaware/7-Del-Admin-Code-SS-7101-3.0
- iowadnr.govhttps://www.iowadnr.gov/environmental-protection/water-quality/private-sewage-disposal-and-septage/time-transfer
- law.cornell.eduhttps://www.law.cornell.edu/regulations/massachusetts/310-CMR-15-301
- revisor.mn.govhttps://www.revisor.mn.gov/statutes/cite/115.55
- gc.nh.govhttps://gc.nh.gov/rsa/html/l/485-a/485-a-39.htm
- webserver.rilegislature.govhttps://webserver.rilegislature.gov/Statutes/TITLE23/23-19.15/23-19.15-12.htm
- app.leg.wa.govhttps://app.leg.wa.gov/wac/default.aspx?cite=246-272A-0270
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
- How this is made and checkedWhat "verified against source" does and does not mean.
From your own code
Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.
pip install refsource
refsource lookup septic-inspection-at-property-transfer state=Delaware
npx -y refsource lookup septic-inspection-at-property-transfer state=DelawareSet your AI assistant up to use this
Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.
{
"mcpServers": {
"referencesource": {
"type": "http",
"url": "https://referencesource.org/mcp"
}
}
}Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project
Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:
When a question needs "Septic system inspection at property sale: which states require it", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `septic-inspection-at-property-transfer`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.What each tool does, and the servers built over single registers: Connect your AI assistant.