I am exhausted and frustrated.

We don't have the dimensions, know where any electric or gas lines are, if there is an exhaust fan, etc.

If you’re making $70k and have the self-awareness to understand where you are financially and where you want to be - you’re better off than many with just pipe dreams.

I would suggest you exhaust all other sources of cheap information first.

My fear with repairs on 100 year old stacks is that we won't be able to find any solid pipe to tie into and will have a forced whole replacement.I just saw another fully-occupied building that has 12 older waste stacks and got a knot in my stomach at the thought of having to displace residents to do the updates.  

If water came up through the drains, complain to the City of Chicago about poor/malfunctioning  sewers.If water came in due to collapsed/clogged drain pipes.

Doors (interior): est 15 doors, 2700Windows (18): 7200 (real bid not estimate)Drywall: 13000Painting (interior): 8100Electrical: bids from 11k-21k includes all fixtures, outlets, etc…Plumbing: 11k-18k (including new water service 1” pipe, and all fixtures)HVAC: 22k (new systems, new ductwork) This also seems high to me, thoughts?

Once you exhaust those do portfolio

There is going to be a special assessment soon of about 2,000 + 2 years of an additional 150/month.I can't deal with tenants calling me constantly with every little thing that is wrong (my pipes tend to clog) so rental would be contingent on tenant handling these things on their own.If I do sell, I would put the money in a mutual fund.What do you think?

There is a a leaky faucet in third floor bathroom which has created damage to second floor's bathroom ceiling in addition to some other possible pipe/water issue as it was mentioned that after taking a shower water was found directly outside of the bathroom on the floor of the third floor apartment .