Have the basement fixed, clean the walls with a bleach spray, put in a dehumidifier and open heat/cooling vents to air out the basement. if that doesn't completely stop it, drylok the walls.

All of the units had radiators in them before the building was converted to gas forced air, so we had to patch a few spots in all 19 units.

@Steve Orluski, rent it for a year or two (maybe Air B&B?) 

I read a passage that basically said "Two people are better off than one, because they can help each other succeed.

Im familiar with bel air Edison and waverly from years ago.

Dishwashers, fireplaces, garbage disposals, electronic air filters, water softeners, garage doors, door openers and any other appliance or fixture, are not warranted by Landlord.

Make them change burned bulbs, air filters, and the like using their money.If you pay them for no "service call", you are promoting even less maintenance in your property. 

finally a Bedroom should have an egress directly to the outside, whether a door or a window that opens with the opening being a minimum of 5 square feet (ground floor) with minimum opening dimensions of 20" and 30" (to allow a firefighter with air tanks to crawl through it). 

There are cranes in the air in every major market so a lot of the workers have moved into those areas for more pay. 

Just wanted to feel it out in the forum to see anyone had any insight on the Air B-n-B regulations in San Diego.