What Is Maryland’s Sprinkler Law for New Homes?

Maryland requires automatic fire sprinklers in new one- and two-family dwellings and townhouses: the Maryland Building Performance Standards (MBPS) adopt the sprinkler section of the 2021 International Residential Code (IRC), Section R313, without change, and Public Safety Article 12-504(a)(1)(iii) bars counties and municipalities from adopting local amendments that weaken it. Since October 1, 2020, Public Safety Article 6-305(a)(3) has also required the State Fire Marshal to enforce the sprinkler installation requirements for new one- and two-family dwellings.

This article is for builders, developers, architects and owners planning new houses or townhouses in Maryland. It explains what the law requires, how Maryland compares with the model code and with neighboring states, which dwellings are covered, who reviews and inspects the systems, and the dates behind the rule, from the 2012 ban on local opt-outs to the State Fire Marshal’s 2020 enforcement duty.

What Maryland’s Sprinkler Law Requires in New Homes

The MBPS is COMAR 09.12.51, administered by the Maryland Department of Labor. Regulation .04A(2) incorporates the 2021 IRC, and the Department required local jurisdictions to begin enforcing the 2021 codes by May 29, 2024. As of November 2026, the regulation still incorporates the 2021 editions.

IRC Section R313 sets the requirement in two parts. Section R313.1 requires an automatic residential fire sprinkler system in townhouses, and Section R313.2 requires one in one- and two-family dwellings. Each system may be designed and installed to IRC Section P2904 or to NFPA 13D, the standard for sprinkler systems in one- and two-family dwellings and manufactured homes.

Both sections exempt additions and alterations to an existing dwelling that has no sprinkler system. Maryland’s changes to the IRC, listed in COMAR 09.12.51.04C, leave Section R313 untouched. The one sprinkler change sits in the plumbing chapter: Regulation .04C(6) deletes the Section P2904.1 sentence that excuses a backflow preventer between the sprinkler system and the water distribution system when the system meets NFPA 13D or P2904, uses Section P2906 piping, holds no antifreeze and has no fire department connection.

Plumbing itself stays outside the MBPS. Regulation .04C(4) places IRC Chapters 25 to 33 outside its scope and refers to the local plumbing code and the plumbing code adopted under Title 12 of the Business Occupations and Professions Article. Where the Washington Suburban Sanitary Commission (WSSC Water) serves the lot, residential sprinkler backflow follows the WSSC Plumbing and Fuel Gas Code, and testable assemblies are tested at installation and every year after by WSSC-licensed plumbers who are certified cross-connection technicians.

The fire code is the other half of Maryland’s two-code system, but it leaves one- and two-family houses out. The State Fire Prevention Code (SFPC), COMAR 29.06.01, does not apply to buildings used only as dwellings for no more than two families (COMAR 29.06.01.03), so the State Fire Marshal’s role in those houses comes from Public Safety Article 6-305(a)(3) rather than from the fire code. DGA’s article on how Maryland’s building code and its NFPA 1 and 101 fire code divide the work explains where each code governs.

How Maryland’s Sprinkler Law Compares With Neighboring States

Maryland kept the IRC requirement for detached houses where several of its neighbors did not. As of November 2026, New Jersey requires sprinklers in new townhouses but not in one- and two-family dwellings, Pennsylvania excludes IRC Section R313.2 by statute, and Sussex County, Delaware exempts both dwelling types in its 2021 IRC adoption. The table sets out each rule and its source.

Figure 1: New-Home Sprinkler Rules: Maryland and Its Neighbors

Jurisdiction	Rule for new homes (as of November 2026)	Basis
2021 IRC (model code)	Sprinklers required in townhouses and in one- and two-family dwellings, designed to P2904 or NFPA 13D	IRC Sections R313.1 and R313.2
Maryland	Sprinklers required in townhouses and in one- and two-family dwellings; counties and municipalities may not weaken the rule	MBPS, COMAR 09.12.51.04A(2); Public Safety Article 12-504(a)(1)(iii)
New Jersey	Sprinklers required in townhouses where the permit or development application was submitted after July 10, 2024, designed to P2904 or NFPA 13D; the IRC requirement for one- and two-family dwellings not adopted	One- and two-family dwelling subcode, New Jersey Administrative Code (N.J.A.C.) 5:23-3.21; Department of Community Affairs (DCA) 2026 code adoption
Pennsylvania	IRC Section R313.2 excluded; the builder must offer a sprinkler system as an option at the buyer’s expense, with information on its cost and possible benefits, at or before the purchase contract	Pennsylvania Construction Code Act (Act 45 of 1999), section 901(g), added by Act 1 of 2011
Delaware (Sussex County)	One- and two-family dwellings and townhouses exempt from Section R313; building codes are adopted county by county	Sussex County Ordinance 2851, adopting the 2021 IRC, effective January 1, 2023

For a builder working across a state line, a single-family plan that needs no sprinklers in New Jersey, Pennsylvania or Sussex County needs a sprinkler design, a water supply check and sprinkler review in Maryland. Pennsylvania takes a disclosure approach instead. Section 901(g) of its Construction Code Act requires the builder of a one- or two-family dwelling to offer a sprinkler system at the buyer’s expense and to give the buyer information on the initial and ongoing cost and on the possible benefits.

Which Dwellings Maryland’s Sprinkler Law Covers

Maryland’s sprinkler requirement follows the IRC’s scope. IRC Section R101.2 covers detached one- and two-family dwellings and townhouses not more than 3 stories above grade plane, each with a separate means of egress. Residential buildings outside that scope, such as apartment buildings, are built under the 2021 International Building Code (IBC) with NFPA 13 or NFPA 13R systems, and DGA’s guide to choosing between NFPA 13, 13R and 13D explains the split. In Maryland, the county building permit reviews sprinklers to NFPA 13 (2019) through the 2021 IBC, while the State Fire Prevention Code (NFPA 1, 2024) references NFPA 13 (2022).

Within the IRC’s scope, the way the house is built decides the answer. OSFM’s memorandum of May 17, 2021, Requirements for Automatic Residential Fire Sprinkler Systems in One- and Two-Family Dwellings, states that new site-built and modular homes need sprinklers and that manufactured homes do not. Modular homes are covered through COMAR 09.12.52.07, which applies the same IRC requirement, and Public Safety Article 9-202(b) requires industrialized buildings to meet the State Fire Prevention Commission’s residential sprinkler standard.

Manufactured homes built to the federal Department of Housing and Urban Development (HUD) code fall under HUD rules and COMAR 09.12.52.15, which do not require a residential sprinkler system. COMAR 09.12.52.15G(1) accepts a manufactured home that bears the HUD label in every Maryland locality as meeting local safety requirements, without further investigation, testing or inspection.

Two other cases sit outside the requirement. Additions and alterations to an existing house without sprinklers are exempt under the Section R313 exceptions, and Washington County applies that rule unless the addition is used as a dwelling unit. A property not connected to an electrical utility is the one case where a county or municipality may still adopt a local amendment that weakens the requirement (Public Safety Article 12-504(a)(3)(i)).

Figure 2: Does a New Maryland Home Need Sprinklers?

New residential construction in Maryland

Which case applies?

Site-built or modular house, or a townhouseSprinklers requiredIRC Section R313; NFPA 13D or IRC Section P2904

Manufactured (HUD-code) homeNo State requirementHUD rules and COMAR 09.12.52.15

Addition or alteration to a house without sprinklersExemptSection R313.1 and R313.2 exceptions

Lot not connected to an electrical utilityLocal amendment allowedPublic Safety Article 12-504(a)(3)(i)

DGA prepares sprinkler drawings and hydraulic calculations for houses, townhouses and apartment buildings across New York, New Jersey, Pennsylvania, Maryland and Delaware. Project briefs get confirmation and preliminary code feedback within one business day. See where DGA works →

Who Reviews and Inspects Residential Sprinklers in Maryland

The county or municipal permit office is the first stop. Maryland leaves MBPS enforcement to local jurisdictions, which under Title 12 of the Public Safety Article carry out at least plan review, building permits, inspections and use and occupancy certificates. Depending on the county, the sprinkler design is checked with the house permit or on a separate sprinkler permit, by the building official or by a county fire office.

The State Fire Marshal has a statutory duty as well. Public Safety Article 6-305(a)(3), in force since October 1, 2020, requires the State Fire Marshal to enforce any requirements relating to the installation of automatic sprinkler systems in new one- and two-family dwellings. DGA’s guide to when the Maryland State Fire Marshal reviews plans covers OSFM’s wider review role.

Washington County is one current example. Its Division of Permits and Inspections issues a Sprinkler and Fire Suppression Permit, applied for online, and the division’s July 29, 2026 permit memo requires a licensed sprinkler contractor on every sprinkler permit. Plans for single-family dwellings need no professional seal, while plans for apartments, condominiums and townhomes must be sealed. The sprinkler permit can issue ahead of the building permit, and the building permit is not held up for sprinkler approval.

Washington County’s residential inspections cover only the sprinkler system and are usually made by the building or fire inspector, in person, with no photographs accepted. Other counties route the work differently, and DGA’s article on how fire protection plan review works in Maryland maps the county fire offices and OSFM. Montgomery County, for one, lists NFPA 13 (2019), including NFPA 13R and 13D, in its fire code regulation, Executive Regulation 14-24, effective December 10, 2024.

Maryland Residential Sprinkler Dates and Local Opt-Outs

The 2009 edition of the MBPS, administered at the time by the Department of Housing and Community Development, required sprinklers in all new residential buildings. Several jurisdictions then used their local amendment authority to opt out of that requirement, according to the Department of Legislative Services’ 2012 fiscal and policy note on House Bill 366.

The General Assembly closed that door in 2012. Chapters 265 and 266 of 2012 (Senate Bill 602 and House Bill 366) added Public Safety Article 12-504(a)(1)(iii), which bars local amendments that weaken the automatic fire sprinkler provisions for townhouses and one- and two-family dwellings. The law took effect October 1, 2012, applies only prospectively and does not affect a building permit applied for before that date.

Section 12-504(a)(3) sets out two exceptions. The first has no end date: the bar does not apply to standards for a building permit on a property not connected to an electrical utility. The second ran only until January 1, 2016 and covered a new one- or two-family dwelling on a lot with a valid public works utility agreement executed before March 1, 2011, or on a lot served by an existing water service line smaller than a nominal 1 inch, approved and owned by the water system, installed before March 1, 2011 and fully operational to the curb stop or meter pit at the property line.

Figure 3: Maryland’s Residential Sprinkler Law, 2009 MBPS to 2024

2009 MBPSThe MBPS requires sprinklers in all new residential buildings; several jurisdictions then amend the requirement out

October 1, 2012Public Safety Article 12-504(a)(1)(iii) bars local amendments that weaken it, for permits applied for from that date

January 1, 2016The temporary exception for older lots with utility agreements or small water service lines ends

October 1, 2020Public Safety Article 6-305(a)(3) requires the State Fire Marshal to enforce the installation requirements in new one- and two-family dwellings

May 29, 2024Local enforcement of the 2021 IRC required, with Section R313 unchanged

Stricter local rules remain open. Section 12-504 restricts only amendments that weaken the sprinkler provisions, and any local amendment must reach the Department of Labor at least 15 days before it takes effect, or within 5 days after an emergency adoption (Public Safety Article 12-504 and COMAR 09.12.51.05). Compliance is checked through the local permit, its inspections and the use and occupancy certificate, with the State Fire Marshal’s enforcement duty behind them for one- and two-family dwellings.

Frequently Asked Questions

This article is general information, not a code determination for any project. Code editions, county amendments and reviewer practice change; confirm the adopted code and the reviewing office for the project.