Accessory Dwelling Units (ADU) Are Coming to Prince George’s County: What Homeowners and Buyers Need to Know

If you own a single-family home in Prince George’s County, the way you think about your basement, garage, or backyard may be about to change.

Maryland has taken a major step toward expanding Accessory Dwelling Units (ADUs) across the state. For homeowners in Prince George’s County, this could create new opportunities for multigenerational living, additional housing and—in some situations—rental income.

But before you start converting the garage or drawing plans for a backyard cottage, there are some important details to understand.

What Is an ADU?

An Accessory Dwelling Unit, commonly called an ADU, is a secondary residential unit located on the same property as a primary single-family detached home.

Depending on the property and local regulations, an ADU could potentially take several forms:

• A basement apartment
• An attached addition with its own living space
• A converted garage or accessory structure
• A detached backyard cottage
• An in-law or multigenerational suite

An ADU generally includes the basic features necessary to function as a separate living space, such as sleeping, bathroom and kitchen facilities.

Under Maryland's new law, an ADU is considered secondary to the primary single-family detached home and generally cannot be larger than 75% of the size of the primary dwelling.

What Changed in Maryland?

Maryland enacted HB 1466, Chapter 197, establishing a statewide policy encouraging the creation of ADUs to help address the state's housing needs.

The law became effective October 1, 2025.

However, there is another date Prince George’s County homeowners should know:

October 1, 2026

Maryland requires applicable counties and municipalities to adopt local laws authorizing ADUs by October 1, 2026.

That distinction is important.

The state law does not mean that every Prince George’s County homeowner can automatically build an ADU today without going through the appropriate zoning, permitting and building-code processes. Prince George’s County and applicable municipalities still have responsibilities for implementing local requirements consistent with Maryland law.

Why ADUs Could Be a Big Deal in Prince George’s County

Prince George’s County has a housing characteristic that makes ADUs particularly interesting: many communities have established single-family homes with basements, garages and sizable lots.

For some homeowners, an ADU could allow them to make better use of property they already own.

1. Multigenerational Living

Imagine having an aging parent close enough to help when needed—but still giving them privacy and independence.

Or perhaps an adult child wants to return home while saving money to purchase their first property.

An ADU could potentially provide a separate living environment while keeping family members on the same property.

2. Potential Rental Income

One of the most talked-about benefits of ADUs is the possibility of creating an additional rental unit.

For example, a homeowner could potentially convert qualifying space into an ADU and rent it to a long-term tenant, subject to applicable County, municipal, licensing, zoning and other requirements.

That income could help offset:

• Mortgage payments
• Property taxes
• Home maintenance
• Retirement expenses
• Renovation costs

Homeowners should never assume a proposed ADU can legally be rented until the property's specific requirements have been verified.

3. Aging in Place

ADUs may also create interesting possibilities for homeowners approaching retirement.

Instead of immediately selling a longtime family home, some homeowners may eventually have options to restructure how the property is used.

A separate unit could accommodate a caregiver, family member or other occupant while allowing the homeowner to remain in the community.

4. More Flexibility for Buyers

ADUs could also change what buyers look for when purchasing homes in Prince George’s County.

A buyer may begin looking beyond the traditional bedroom and bathroom count and ask:

Does this property have ADU potential?

A large unfinished basement, detached garage, side entrance or oversized lot could become more important features when evaluating a home.

Could an ADU Increase Your Property Value?

Possibly—but there isn't a universal dollar-for-dollar formula.

A legal, properly permitted and functional ADU could make a property more attractive to buyers seeking multigenerational housing or additional flexibility.

However, buyers and sellers should distinguish between a true legal ADU and a basement that simply happens to contain a bedroom, bathroom and second kitchen.

Permits, zoning compliance, appraisal treatment and financing can all affect how additional living space is valued.

Don't Convert Your Basement Just Yet

This may be the most important part of the conversation.

Having enough space for an apartment does not automatically make that space a legal ADU.

Before investing thousands of dollars in construction, homeowners should determine:

• Whether an ADU is permitted on the specific property
• Whether the property falls under County or municipal regulations
• Applicable size and setback requirements
• Building, electrical, plumbing and fire-safety requirements
• Whether additional parking requirements apply
• Whether water and sewer capacity creates additional requirements
• What permits are required
• Whether rental licensing is required if the unit will be leased
• Whether HOA or other private restrictions affect the property

Rules can vary depending on the property.

What About HOAs?

This is another area homeowners need to investigate carefully.

State and local zoning rules are only part of the picture. A property may also be subject to HOA covenants or other private restrictions.

Before designing or constructing an ADU, homeowners should have the applicable documents reviewed and determine what restrictions may affect their plans.

ADUs Could Create Opportunities for Real Estate Investors, Too

Investors should pay attention to this change.

A single-family property that previously had limited income potential could become more attractive if it has the physical characteristics and legal ability to accommodate an ADU.

However, investors should run the numbers carefully.

The calculation isn't simply:

Purchase House + Build ADU = Profit

A proper analysis should include acquisition cost, renovation costs, ADU construction, permits, financing, taxes, insurance, projected rent, vacancy, maintenance and the property's projected resale value.

The ability to create an ADU should be verified during due diligence—not assumed when making an offer.

Thinking About Buying a Home With ADU Potential?

This is where having a real estate strategy becomes important.

When evaluating a Prince George’s County property for possible ADU use, we can look beyond the listing photos and examine characteristics such as the lot, basement configuration, existing accessory structures, entrances and overall property layout.

From there, the appropriate County or municipal agencies and qualified professionals can determine whether the concept is actually feasible.

The Bottom Line

Accessory Dwelling Units could become one of the more significant changes affecting single-family housing in Prince George’s County.

They have the potential to provide homeowners with more flexibility, help families create multigenerational living arrangements and expand the County's housing options.

But ADU potential and an approved ADU are two very different things.

Before buying a property specifically for an ADU—or spending money converting your existing home—verify the current zoning, permitting and building requirements for that specific property.

Curious Whether Your Prince George’s County Home Has ADU Potential?

Gallery Collective can help you look at your property through a real estate and investment lens.

Whether you're considering selling, buying a property with ADU potential, creating space for family or evaluating how an ADU could affect your home's marketability, let's start with the property and your goals.

This article is provided for general real estate information and is not legal, zoning, tax, construction or financial advice. ADU requirements are evolving, and property owners should verify current requirements with Prince George’s County, the applicable municipality and qualified professionals before making construction or investment decisions.