As @FrogDive0 pointed out, Lake Phoenix is an option but, it is a 3.5 - 4 hour dive. However, I’ve heard great things about it and will probably dive there before the summer’s out.
It probably seems strange that a guy from NC would comment about diving in the Baltimore area but, my daughter has been living in Baltimore for the past four years so, I couldn’t resist. Another option, albeit pricey, is the National Aquarium in Baltimore. Last time I checked, it was around $200 to be a guest diver there.
The National Aquarium also has a volunteer diver program where you assist in maintaining the underwater exhibits. It would require you to do some work but, at least you’d be diving. A good friend of my son-in-law is a volunteer diver at the aquarium.
If you’re interested in either of those, go to the National Aquarium home page, look for "Visit Us", then look under "Tours and Experiences" and then under "Close Encounter".
Hope this helps.