Maryland Building Performance Standards

The statutory basis

• MBPS — Md. Public Safety Article, Title 12, Subtitle 5, § 12-501 et seq. Regulations at COMAR 09.12.51.
• MBRC — Md. Public Safety Article, Title 12, Subtitle 10, § 12-1001 et seq. Regulations at COMAR 09.12.58. Effective since June 1, 2001.
• Administration — Maryland Department of Labor, Division of Labor and Industry, Building Codes Administration (labor.maryland.gov/build/buildcodes.shtml).

State adoption of I-Codes as MBPS

The MBPS incorporates the IBC, IRC, IECC, and other International Codes, modified by the state. Key features of the adoption process:

• 18-month adoption window. The Department of Labor must adopt subsequent I-Code versions within 18 months of ICC publication.
• Review-and-modify. Before adoption, the Department reviews I-Codes and makes modifications to align with other MD laws and energy/efficiency policy.
• Stringency cap on most codes. The Department generally cannot adopt modifications more stringent than the IBC base code — except for energy conservation.
• Energy stringency floor. The Department may adopt energy conservation requirements more stringent than IECC, but not less. This is where the real state-level policy lever sits.
• First-printing rule. The adopted MBPS reflects the "first printing" of each I-Code; interim amendments or subsequent printings apply only if specifically adopted.

MBRC — the existing-building track

Maryland's adoption of the IEBC as the MBRC is a specific structural choice. Work on buildings over one year old follows MBRC rather than the new-construction MBPS. Implications:

• A 2021 IEBC base with COMAR 09.12.58 modifications governs.
• Maryland Building Rehabilitation Code Advisory Council provides input on MBRC content.
• Design teams handling renovation, adaptive reuse, historic rehab, or existing-building fit-out reference MBRC provisions rather than trying to apply new-construction MBPS requirements across the board.
• Cost and preservation outcomes often favor MBRC pathways on older buildings because IEBC-derived provisions accommodate existing conditions more realistically.

Designers used to jurisdictions that apply IBC/IRC uniformly across new and existing (with IEBC as optional alternate) need to recalibrate. In MD, MBRC is the default for existing-building work.

Local amendment authority

After the state adopts a new I-Code edition as MBPS, local jurisdictions have up to 12 months to adopt locally — with the opportunity to amend further. The constraints:

• Local amendments may make most provisions stricter but not less stringent than MBPS minimum.
• IECC and Maryland Accessibility Code (MAC) can only be made more stringent locally.
• No central compilation. The state doesn't maintain a consolidated list of all local amendments. Designers check each jurisdiction individually.

The jurisdictional variation is real:

Baltimore City

Adopts the I-Code suite (currently including 2021 IBC/IECC) with local amendments. Has a mandatory Green Construction Code based on the 2018 IgCC, effective since May 18, 2020, with subsequent amendments. Recent zoning reforms have explored single-stairway allowances up to six stories in residential and off-street parking minimum eliminations.

Montgomery County

Adopts the 2021 IBC Code Suite via Executive Regulation 13-24, with amendments that go substantially beyond state minima. Requires ASHRAE 90.1-2022 for energy compliance, mandates energy modeling for most projects, and incorporates EV-Ready parking and on-site energy storage requirements. Pending all-electric new construction mandate targeting December 31, 2026.

Washington County (rural Western MD)

Adopted the 2021 MBPS with local amendments effective July 1, 2024. Less stringent locally-amended overlay than Montgomery County but still requires verification per jurisdiction.

St. Mary's County (Southern MD)

In the process of adopting the 2021 MBPS and reviewing the I-Codes for local modifications.

Baltimore County, Prince George's County, Anne Arundel County, Howard County, Frederick County, Carroll County, and the Eastern Shore counties each have their own adopted-code positions worth verifying on specific projects.

CHAP / historic overlay on top of code

In Baltimore City, the Commission on Historic and Architectural Preservation (CHAP) adds exterior-review authority on designated properties that layers on top of MBPS/MBRC code review. See our Baltimore CHAP essay for the CHAP-specific pattern. Similar Maryland Historical Trust and county-level historic frameworks apply elsewhere in the state.

What out-of-state designers should expect

• Two base codes, not one. MBPS for new construction, MBRC for existing buildings. Identify the applicable track at pre-design.
• State-level modifications to I-Codes. Don't assume model-code provisions apply unchanged. The "first printing" doctrine and COMAR 09.12.51/.58 modifications matter.
• Energy performance is the high-stringency lever. MD allows both state and local governments to go above IECC/ASHRAE 90.1 baselines. Montgomery County, Baltimore City, and Howard County use this actively.
• Accessibility can exceed IBC/ADA. Maryland Accessibility Code can be locally amended more stringently. Verify jurisdictional requirements.
• Local amendments aren't centralized. Call the code official or check the jurisdiction's amendments ordinance; don't extrapolate from a neighboring county.
• Adoption lag. A jurisdiction mid-way through adopting a new MBPS edition may be enforcing the prior edition on current projects. Confirm the effective code as of the permit application date.

How this compares to neighboring states

• Virginia. Virginia Uniform Statewide Building Code (USBC) adopted statewide with limited local amendment authority — significantly more uniform than MD's layered model. See our Richmond DPDR essay.
• Pennsylvania. PA Uniform Construction Code under 34 Pa. Code Ch. 401 adopts I-Codes with state amendments. Local opt-in exists; some municipalities enforce UCC through their own inspection agencies, others through third-party agencies.
• New Jersey. NJ Uniform Construction Code under N.J.A.C. 5:23 is statewide-uniform with no local amendment authority — Construction Officials administer at city level but the code base doesn't vary. See our Camden UCC essay.
• Delaware. No statewide building code historically; adoption is at the city/county level. Some DE jurisdictions enforce I-Codes, others use their own frameworks.
• Maryland. State adoption with explicit local-amendment authority. More variation than NJ/VA, less variation than DE.

What to do with this

If you're designing new construction in MD: identify jurisdiction first, confirm adopted MBPS edition, then check local amendments ordinance. Energy code compliance path and MAC compliance are the usual hotspots.

If you're renovating existing: confirm MBRC applicability and reference the COMAR 09.12.58 modifications against the IEBC base.

If you're working Montgomery County, Baltimore City, Howard County, or other aggressive-adopter jurisdictions: plan for higher energy performance and broader environmental mandates than state minima.

For the full MD permitting framework, see our Baltimore Permit Navigator. For contractor licensing alongside code, see MD Contractor Licensing Navigator.

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