Hopefully this may help until someone familiar with maryland comes along.
http://www.aacounty.org/IP/PAC/PermitRequired/PermitRequiredPlumb.cfm#.U6ovifldUYk
http://www.aacounty.org/IP/PAC/PermitRequired/PermitRequiredMisc.cfm#.U6ov-fldUYk
From that county web site. Plenty more on that site, I just used these because they relate specifically to the plumbing end.
http://www.aacounty.org/IP/PAC/PermitRequired/PermitRequiredPlumb.cfm#.U6ovifldUYk
http://www.aacounty.org/IP/PAC/PermitRequired/PermitRequiredMisc.cfm#.U6ov-fldUYk
From that county web site. Plenty more on that site, I just used these because they relate specifically to the plumbing end.