On January 16, 2026, a town inspector walked the lot at 9 New Jersey Avenue and found a house that did not match its paperwork. The property carried an approved Certificate of Appropriateness from July 11, 2023, covering an addition and a historical renovation. What had actually been built was closer to a full demolition and new construction. The town's letter was direct: the work on the ground exceeded what the Historic District Commission had approved, an as-built fine applied, and the owner would need to file an entirely new application, this time for a new dwelling, before the property could be brought into compliance.
That letter is a public record, not a headline, and it will not show up in a portal listing. But it points to something every buyer, seller, and agent on the island should understand before a sale closes: on Nantucket, a Certificate of Appropriateness is not a formality you file and forget. It is a document that has to keep matching the house, and the two can drift apart quietly over the course of a renovation, often for years, before anyone checks.
The whole island is the historic district
Nantucket is unusual even among Cape and Islands towns in how completely its preservation rules cover the map. The entire town, along with Tuckernuck and Muskeget, sits inside a National Historic Landmark district. That is not a downtown overlay or a handful of protected blocks. It means virtually every exterior change on virtually every parcel needs a Certificate of Appropriateness from the Historic District Commission before a building permit can be issued.
The reach of that requirement surprises people who assume small jobs are exempt. A fence that does not need a building permit still needs HDC sign-off if it is visible from a public way. A shed under 120 square feet still needs review before it goes in the yard. Driveway aprons, color changes, and roofline work all route through the same commission. The HDC meets weekly, on Tuesdays at 4 p.m. at the Public Safety Facility on Fairgrounds Road, and its design guidance document, Building With Nantucket In Mind, is the reference point staff and applicants use to judge what will pass.
For straightforward requests, the process moves fast. Window replacements and repainting can clear in two to four weeks. Additions, new construction, and anything involving significant massing changes typically run two to six months, longer if the commission asks for revisions. That range matters for renovation timelines, but it is not the part of the process that creates risk at closing. The risk comes after approval, once construction actually starts.
| Project type | Typical HDC review time |
|---|---|
| Window replacement, repainting, minor repairs | 2 to 4 weeks |
| Additions, new construction, major alterations | 2 to 6 months, depending on revisions |
A Certificate of Appropriateness is a promise about a specific building
Once the HDC approves a project, it issues a Certificate of Appropriateness that is valid for three years from the date of issuance. The language on the certificate itself is unambiguous: no structure may differ from the approved application. That is not a loose standard. It means the COA is not permission to renovate the property in general. It is permission to build exactly what was drawn, at the scale, siting, and materials that were reviewed.
Renovations rarely stay static for two or three years. Framing decisions shift once a contractor opens up a wall. An owner living off-island for long stretches signs off on changes by phone or email without walking the site. A project that started as an approved addition and historical renovation, on paper, can end up looking like new construction, in practice, without anyone filing a revised application to match. That is the exact gap the town's letter for 9 New Jersey Avenue describes. Nothing about that gap requires bad intent. It requires only that construction outpaces paperwork, which is common on a multi-year island renovation.
The consequence is that the certificate an owner holds may no longer describe the house that exists. And because the certificate is the town's legal record of what was permitted, a mismatch does not resolve itself. It sits until an inspection, a complaint, or a sale surfaces it.
Where this actually shows up at closing
Massachusetts closings on Nantucket typically involve a Municipal Lien Certificate, a document listing the taxes, assessments, and charges that constitute liens against the parcel. It costs $25 per parcel, comes from the Tax Collector's Office on Washington Street, and is standard practice whenever a property is sold, refinanced, or the subject of an insurance claim. It is a useful document, but it is fundamentally a tax and assessment record. It was not built to answer the question of whether the exterior of the house matches its most recent Certificate of Appropriateness.
That distinction is where the friction lives. A buyer's attorney who pulls the MLC and calls it done has not actually confirmed HDC compliance. Confirming that requires a separate step: requesting the property's COA history directly and comparing it against what was built, ideally with someone who has read enough of these files to know what changed between the drawings and the finished structure. On a market where renovated cottages, expanded captain's houses, and rebuilt 'Sconset properties routinely trade for seven figures, that is not a step worth skipping.
Enforcement is not symbolic, either. Violations of the certificate requirement carry a penalty of $300 per day under the town code, with each day treated as a separate violation, and the town has the authority to require a brand new application before a noncompliant structure can be brought current, exactly as it did at 9 New Jersey Avenue.
What buyers, sellers, and agents should actually check
Before a Nantucket purchase and sale agreement gets signed on a renovated property, a few questions are worth asking directly rather than assuming they will surface later.
- Request the full Certificate of Appropriateness history for the parcel, not just the most recent one, from the Planning and Land Use Services office at 2 Fairgrounds Road.
- Compare the approved drawings on file against the current as-built condition, particularly for any addition, renovation, or new construction completed in the past three to five years.
- Ask whether any work was completed after the most recent COA's issuance date, since certificates expire three years from issuance and any later changes need their own approval.
- Pull the Municipal Lien Certificate as usual, but treat it as a tax and assessment check, not a substitute for HDC compliance review.
- If a mismatch turns up, get a clear answer on what a corrected application will require and how long that review is likely to take, since additions and new construction fall on the two to six month side of the HDC's calendar.
None of this requires assuming the worst about a listing. Most Nantucket renovations go through the process cleanly and the paperwork matches the house. But the 9 New Jersey Avenue case is a reminder that the paperwork is the thing being sold along with the structure, and it is worth confirming before it becomes someone else's closing problem.
FAQ
Does an HDC violation show up automatically in a title search? A standard title search and a Municipal Lien Certificate focus on ownership history, taxes, and recorded liens. Neither is designed to catch a mismatch between a Certificate of Appropriateness and the as-built condition of a structure, which is why a direct records request to Planning and Land Use Services is a separate and necessary step.
What happens if a violation is discovered while a sale is already pending? The town can require a new Certificate of Appropriateness application to bring the structure into compliance, along with any applicable fines, which can affect the timeline a buyer and seller had planned around for closing.
Is this only a concern for major renovations or new construction? No. Because the entire town sits within the historic district, even smaller exterior changes such as fences, sheds, and driveway work require HDC review, so the same as-built question applies across a wide range of project sizes.
If you are buying or selling a renovated property on Nantucket and want a clear read on its Historic District Commission paperwork before you're under contract, Chatham Properties Group can help you get the full picture. Request a Private Market Consultation and we'll walk the file with you before it becomes a closing surprise.
