Despite the "common hearsay" aluminium wiring can be safe, provided the correct receptacles/fixtures are used, or the ends of runs were properly pigtailed to copper.You definitely want breakers over fuses and you would want to confirm the existing circuits have the capacity to handle today's electrical loads and that there is additional room in each unit's panel.

I'm waiting for a bid for that work, and early indications are that it could be between 7K and 10K to get the water running, maybe more.  

If you can swing a 4plex, that would get you up and running faster, but there are two reasons you might not want a 4plex.  

i know what Rubs is, the only problem is this doesn't seem accurate it the tenant leaves all the lights on all the time, or leaves the water running by"accident"

Rents are under market by $50-$100 but I wanted to run my numbers on current rents.

You can also google search calculators and find some decent ones if you run out of uses for the BP calcs as a free BP membership user!

You should really learn to evaluate all the expenses and run the numbers, Cha Yang.

I think it was caused by some run-off issues with water.The bottom line is I need to get it fixed.  

If this investment doesn't hurt me in the long run I think I'll be lucky.

I would have the ducts cleaned, furnace/AC system cleaned as much as possible, change the filter, and then run an ozone machine with fans set up to circulate the air for 48 hours.