Boston Building Permits — Cost, Timeline & Process

Boston requires a building permit for most construction, alteration, and repair work that affects structural, electrical, plumbing, or mechanical systems. Permits are issued by the ISD (Inspectional Services Department), the city agency responsible for building permits, housing inspections, and code enforcement at 1010 Massachusetts Avenue.

Boston enforces the 10th Edition Massachusetts State Building Code (780 CMR). The 10th Edition is based on modified 2021 International Codes, including the 2021 IBC and IRC. After the state concurrency period ended June 30, 2025, the 10th Edition became the only Massachusetts building-code edition accepted for new permit applications.

The Key Split: ISD vs. Planning Review

Boston's development process separates building-permit review from planning and zoning review.

ISD (Inspectional Services Department) is the building department. ISD reviews permit applications, issues building permits, and conducts construction inspections.

The City of Boston Planning Department administers development review under Article 80 of the Boston Zoning Code. Boston's current development-review portal and guidance distinguish Small Project Review from Large Project Review:

• Small Project Review generally applies to projects adding at least 20,000 square feet but less than 50,000 square feet, and/or projects creating 15 or more dwelling units.
• Large Project Review applies to new construction exceeding 50,000 square feet, certain changes of use above the applicable threshold, and certain substantial rehabilitation projects.

The project-specific path can also depend on location, use, rehabilitation scope, and other Article 80 provisions. Do not treat “20,000 square feet or 15 units” as the Large Project Review threshold. Boston approved Article 80 modernization amendments in 2025 and is implementing operational changes through 2026, so current Planning Department guidance and the live zoning text should be checked for the filing path and review steps.

Short-Form vs. Long-Form Permits

ISD divides building permit applications into two categories:

Short-Form Permits cover minor alterations, repairs, or replacements that do not change the structure or use of a building — for example, opening a wall for minor electrical or plumbing work, repairing a deck, or replacing roofing materials in kind. The fee is $20 plus $10 per $1,000 of estimated project cost. Owner-occupants of 1–2 family homes may self-perform work on short-form permits.

Long-Form Permits cover major alterations or renovations that change a building's structure or use, as well as applicable new-construction and change-of-occupancy work. Required documents vary by project and applicant type; Boston's current Long-Form guidance lists project information, licensing/insurance documents, plans, and other supporting material as applicable. The fee is $50 plus $10 per $1,000 of estimated project cost.

Both permit types must be applied for through the ISD online portal before any work begins. The permit must be used within six months of issuance.

When You Need a Permit

You generally need a Boston building permit for:

• New construction, additions, and accessory structures (including ADUs)
• Structural alterations, load-bearing wall changes, and foundation work
• Electrical, plumbing, and mechanical (HVAC) changes
• Reroofing and window or door openings in exterior walls
• Swimming pools, most retaining walls above a height threshold, and certain fences
• Change of use or occupancy of any space
• Demolition of any habitable structure

Minor cosmetic work — painting, floor coverings, cabinetry without plumbing or electrical changes — is typically exempt. When in doubt, contact ISD before starting work.

Permit Costs

Boston's ISD building permit fees are based on estimated project valuation:

• Short-form permit — $20 application fee + $10 per $1,000 of project cost
• Long-form permit — $50 application fee + $10 per $1,000 of project cost
• Trade permits (electrical, plumbing, mechanical) — separate permit fees apply for each trade
• Demolition permits — separate fee schedule

Do not rely on third-party fee estimates. Verify the current fee schedule directly with ISD at 617-635-5300 or [email protected] before budgeting.

Typical Timeline

Review times vary with ISD workload, project scope, required outside approvals, and correction cycles.

The Process

1. Determine your permit type: Confirm whether your project needs a Short-Form or Long-Form permit and whether separate planning, zoning, or landmarks review applies
2. Complete required planning/zoning review: If the project triggers Article 80 or other Planning Department review, complete the required review and obtain the approvals needed for permitting
3. Landmarks Commission (if applicable): For properties subject to Boston Landmarks Commission jurisdiction, obtain the required approval for regulated exterior work
4. Create an ISD portal account: Register at the Inspectional Services online portal (onlinepermitsandlicenses.cityofboston.gov/isdpermits/)
5. Prepare documents: For long-form permits, upload the project information and supporting documents required for the selected permit subtype. Depending on the project and applicant, this can include plans, a plot plan, licensing and insurance records, workers' compensation documentation, contracts, and site-safety materials.
6. Submit and pay fees: Apply online or in person at 1010 Massachusetts Ave, 5th Floor; fees are due upfront
7. Plan review: ISD reviews for compliance with 780 CMR; complex projects may require review by external agencies (Parks, Fire, Zoning)
8. Corrections: Respond to review comments and resubmit until approved
9. Permit issuance: Receive permit; work must begin within six months
10. Inspections: Schedule required inspections at each construction phase
11. Final inspection: Pass final inspection to close the permit; obtain Certificate of Occupancy if applicable

Inspections

Typical inspection stages for a residential long-form project include:

• Foundation / footings
• Underground plumbing and electrical
• Framing
• Rough plumbing, electrical, and mechanical
• Insulation
• Drywall
• Final building and trade inspections

Schedule inspections through the ISD portal. Boston states that an inspector will contact the applicant within 48 hours to schedule and confirm the inspection.

Historic Districts

Properties in Boston's designated historic districts require an additional layer of review by the Boston Landmarks Commission before ISD will issue a permit for exterior alterations. Historic districts include Back Bay, Beacon Hill, Fort Point Channel, Bay Village, St. Botolph Street, and others. Whether interior work is within Landmarks Commission jurisdiction depends on the property's designation and the terms of the applicable landmark or district protections; confirm the specific property before assuming an interior project is exempt. Factor this additional step and its timeline into your project schedule.

Common Reasons for Denial or Corrections

• Plans do not comply with 780 CMR (Massachusetts State Building Code)
• Missing engineer or architect stamps on required drawings
• No certified plot plan (required for long-form)
• Zoning conflicts — setbacks, height, lot coverage, or use not in conformance
• Required Planning Department / Article 80 approval or zoning review is incomplete
• Boston Landmarks Commission approval not obtained for historic district properties
• Incomplete contractor licensing or insurance documentation
• Worker's compensation affidavit missing or incorrect

Official Sources

Use Boston's current Short-Form Permit and Long-Form Permit pages for application requirements and fees, and the ISD online portal for applications. For Article 80 thresholds and development review, use the current Boston Planning Department / Bostonplans Development Review guidance. For the state code, use the Massachusetts 10th Edition 780 CMR materials.

Disclaimer: This guide summarizes publicly available information from official City and Commonwealth sources and is provided for general orientation only. It does not constitute legal or engineering advice. Confirm current requirements with Boston Inspectional Services and, where applicable, the City of Boston Planning Department before filing or starting work.