DO NOT BUY A RENTAL IN DC...
My coworker has 3 and is hating life. She was finally able to get a tennant out after 30 months of no payments. DC tennant laws are for the tennant not the landlord and if the tennant knows what they are doing they can royally screw you.
Her story... Started eviction process for no payment, tennant filed an appeal (3 month review), appeal denied, filed another appeal- denied, tennant filed weather appeal (you can not evict if the weather is below a certain temp) appeal approved (Novembe-rish) Had to wait until spring to file another eviction notice, tennant claimed her disabled mother moved in with her (appeal) (6 month review) at 5 months into the review, filed another weather appeal (weather appeal approved) Around January disabled mother appeal was denied (she did not even live with her) evicted last month. Almost $60k in lost rent and $15k in legal expenses. She can claim the loses against her other properties but that is not worth the headache.
MD is better than DC but VA is a better than MD.