Building a secondary living space on the same lot as a primary home has historically meant working through a patchwork of county rules across Maryland, with wildly different requirements depending on where a property happened to sit. A new state law is changing how this kind of in-law suite & ADU construction project gets treated, and homeowners planning one should understand what has actually changed.
What the New Law Actually Requires
Maryland’s Accessory Dwelling Units Act, passed as Senate Bill 891, establishes a statewide policy encouraging these secondary living spaces on lots with a single-family home. Under the enacted legislation, local governments must adopt an ordinance authorizing this kind of construction on qualifying lots by October 1, 2026. Before this law, individual counties could effectively block these projects through restrictive or absent zoning rules, leaving homeowners in some jurisdictions with far fewer options than neighbors just a county away.
Why This Law Changes Things for Homeowners
For years, whether a homeowner could add this kind of secondary space depended heavily and almost entirely on which specific county they happened to live in. Some jurisdictions had streamlined, homeowner-friendly processes, while others had no clear path forward at all. This new statewide policy does not eliminate local zoning authority entirely, but it does require every covered jurisdiction to create a workable path, closing the gap between counties that previously made this kind of project far easier than others.
What Counts as a Secondary Living Space
Under the new law, a qualifying secondary unit generally must include the basic components of a genuinely independent home. Common configurations include:
- A garage conversion with its own kitchen, bathroom, and sleeping area
- An attached addition with a separate entrance from the main house
- A standalone detached structure built in the backyard
- A space sized at no more than seventy-five percent of the primary home
Each configuration has to function as a complete, independent living space rather than simply an extra room connected to the main house. Kitchens, in particular, are what typically distinguish a qualifying secondary unit from a large bedroom or bonus room addition that does not meet the legal definition.
How HOA Restrictions Are Affected
One of the more significant provisions in this new law addresses homeowners associations directly. The law limits how private restrictions, including covenants and deed provisions, can be used to block or unreasonably increase the cost of building a secondary unit. Homeowners in HOA-controlled communities who previously assumed this kind of project was off the table entirely may find that assumption is no longer accurate under the new framework. This shift matters especially for the many Maryland neighborhoods built under HOA governance in recent decades, where restrictive covenants have historically been one of the biggest obstacles to this kind of construction.
Building a Secondary Living Space the Right Way
Because local ordinances are still being finalized in many jurisdictions, working with a builder who tracks these changes closely matters more than it usually would right now. A in-law suite & ADU construction project started today still has to satisfy whatever specific standards a given county ultimately adopts, even as the statewide framework pushes every county toward allowing this kind of construction.
Getting Started on Your Project
This shift opens real options for homeowners who were told in past years that a secondary living space simply was not possible on their property. Back Creek Builders LLC tracks these zoning changes county by county and designs secondary living spaces that meet both state policy and local requirements as they continue to take shape. If you have been considering a space for aging parents, adult children, or rental income, reach out to find out what is now possible on your specific lot, since the answer may be very different than it was just a year or two ago.
