In my experience, the main reason landlords are not prepared for the Baltimore County Rental Inspection is the hardwired smoke detector requirement.
A hardwired smoke detector with a battery backup must be installed on any floor with sleeping areas, and on any floor with a furnace. This usually means one in the hallway on the second floor and one in the basement.
If your rental property is a newer home it may have been built with hardwired smoke detectors. But older homes were not, and the owners typically relied on battery-operated smoke detectors. At the risk of repeating the same point over and over: To satisfy the Baltimore County Rental License requirement you must have hard-wired smoke detectors.
Carbon monoxide (CO) detectors must also be installed in the common area on any floor with bedrooms. Whereas the smoke detector needs to be hard wired, the CO detectors do not. (This is because Baltimore County added the requirement later). You can use a battery operated CO detector, (mounted to a wall or ceiling), or a plug-in CO detector, which can be plugged into any outlet.
Plug-in carbon monoxide (CO) detectors are very convenient because they can be easily moved as needed. If you don’t have an outlet in the common area outside of the bedrooms (the hallway), consider putting a plug-in CO detector in each bedroom. Alternatively, you can purchase a battery-operated CO detector and mount it in the hallway on the wall or ceiling.
A third option is to purchase combination smoke/CO detectors (combos). if you’re installing hard-wired smoke detectors for the first time, the combo will satisfy both requirements at once. If you already have hard-wired smoke detectors, battery-operated or plug-in CO detectors may be your best choice.