There is no much love for the tiny house movement in Maryland.
Statewide, tiny houses have not received any acknowledgement. The local jurisdictions have been left to govern themselves in this regard, and most have not done a good job.

One bright spot happened in Montgomery County in 2019. The county council voted unanimously in favor of zoning changes that made it easier for residents to build accessory units on their properties.

Previously, there was a requirement that a neighborhood could only have one ADU every 300 or 500 feet. Also eliminated was a ban on tiny homes on smaller lots. These changes were adopted by the council, despite strong resistance from locals. There was even a protest on the day of the vote, which is all you need to know how friendly the state is to the tiny movement.

Generally in most of the state, laws enabling tiny houses are few and far between. For instance RVs are mostly forbidden from private property, whether owned or rented.

Like many other states, the more rural a tiny homeowner is willing to go in Maryland, the more they are likely not to break any laws. Maryland is however seeing a growing tiny house movement, particularly emboldened by their proximity to Washington, DC, which is more welcoming and friendly to tiny houses.