Converting part of a single-family home into an apartment is common in the National Capital Region, as it provides income for homeowners, and an option for apartment-seekers — but not in Fairfax County, Virginia.

Fairfax County’s Board of Supervisors seems set to approve changes Tuesday to its 42-year-old zoning ordinance that would make it easier to rent a converted apartment.

As the sole local jurisdiction decreeing that “accessory living units” can only be inhabited by residents older than 55 or who have a disability, some Fairfax County residents have illegally converted basements and garages.

Recently, the county’s planning commission recommended removing the age and disability requirements, as part of plans to modernize zoning restrictions.

Converted apartments in single family homes are defined by having a stove.

Over the years, illegal boardinghouses in the county have led to overcrowding, and in some cases fires, caused by extension cords providing alternative cooking sources.

Jeff McKay, chair of the supervisors, said a proposed new process set to be decided on at a Tuesday board meeting would make it easier for homeowners to get the converted dwellings approved and enable officials to inspect such units for safety.

Opponents have expressed concerns that allowing more residents could make it more difficult to park in established neighborhoods. The amendment would require homeowners to ensure tenants could park on their property.

If the board adopts the modernized zoning ordinances, they are expected to take effect July 1, 2021.