Charles County residents have been picking up the phone about backyard apartments. Far fewer have picked up a permit application.
County planning staff told the Charles County Planning Commission on Monday, Oct. 5, that fewer than a dozen applications for accessory dwelling units, known as ADUs, have been filed since the county’s new rules took effect, along with what staff called dozens of phone calls. A staff member said the effective date was, as best they recalled, the end of August, which would put the count at roughly five weeks of activity. The figure was offered anecdotally rather than as a formal tally, and staff cautioned that a filed application does not mean the applicant meets every requirement or will receive a permit. “We’ve had a lot of interest,” a staff member said, after a planning commissioner asked whether anything had moved through the system yet.
The rules in question came from Proposed Bill 2026-06, Zoning Text Amendment 25-189, which the Board of County Commissioners passed unanimously on July 7. ADUs are now allowed in any zone that permits single-family detached homes, with one per lot, and are not allowed on lots with a duplex, triplex or apartment building. The change eliminated the old requirement that a detached ADU use no more than half of its building for living space, a rule that, by the county’s own example, meant a 1,000-square-foot apartment needed a 2,000-square-foot building. It also scrapped off-street parking requirements and opened the door to internal ADUs in future townhome communities, though new units must still follow homeowners association rules. The July release said the bill raises the maximum ADU size to meet state law without giving a figure; the March proposal would have capped units at 1,000 square feet or 75 percent of the main home, whichever is smaller.
The push came from Annapolis. House Bill 1466, which took effect Oct. 1, 2025, told counties and municipalities to adopt a local law authorizing ADUs on land with a single-family detached home by Oct. 1, 2026. Under the state’s guidance for local governments, localities may not set the size limit below 75 percent of the primary home, and a jurisdiction that wants to impose parking requirements must first complete a parking study. Charles County’s housing strategy had already listed ADU expansion as a one-to-two-year goal. The Town of La Plata, which writes its own zoning, adopted its version Sept. 8, and the Chronicle’s earlier reporting on the county’s changes tracked the bill through the summer.
Why interest outruns paperwork is not something staff attempted to quantify, but they did point to one obstacle. Health department septic regulations, a planning staff member said, remain “one of the hurdles to seeing more ADUs built in the rural parts of the county,” and the county continues to field questions from the public about them. The county’s July summary said sewage and septic rules for rural ADUs were unchanged. Staff said the commissioners have proposed legislative changes to make health department regulations simpler and utility installations easier to meet, but there is no update until those proposals go to the General Assembly in the new year.
Meanwhile, planners are preparing the permitting side. Staff said they are updating the permitting team on what to look for and making sure the statistics being tracked can be reported in coming years, including how many ADUs are built on private septic systems versus public sewer. That tracking may eventually answer the question the early numbers cannot: how many of those dozens of callers end up with a unit.
ADUs sit slightly apart from the county’s broader affordable housing push. Staff said the units will be counted separately from the roughly 1,250-home shortfall for households earning 30 to 80 percent of area median income, because an ADU is not necessarily offered at a restricted rent. Instead, staff described ADUs as a useful bridge for younger families or older households, a step between renting and owning or between starting out and a first place of their own. The ADU discussion was part of a one-year review of the strategy that the Chronicle covered in its report on the plan’s first year, and the Planning Commission’s separate mixed residential communities amendment, which the commissioners advanced 3-1 in September, would open still more small-home options if it is adopted.
For homeowners weighing a garage apartment, an in-law suite or a converted outbuilding, the practical message from the Oct. 5 briefing is that the zoning door is open but the site still has to qualify, and the county plans to report real permit counts once it has them.
