Harden up, and have some cash set aside for things like this--it's just part of the business, and not quiet at the "Horror Story" level yet.It can get way worse.In the future, be careful when vetting possible renters.See some of the postings in this forum about renter vetting.As to your question directly, what you can and can't do, and the associated dates are controlled by your state, (and and maybe city) laws of the property address.Maybe posting the property state and city will help responses.Bend Oregon will probably be different than Las Cruses New Mexico, which will probably be different than many parts of New Jersey.Good Luck!

So for example I'm very conservative and don't want any debt on them because I feel this hardens them in case of a severe recession.

@Amita Harden thank you.

Harden I'll connect with you via PM.

you could use level quick, which is a resin concrete mix that hardens in about an hour.

@Harden Barkley You are right on target.  

I do the same for plumbing as well where I "Harden" the rental by upgrading diameter on the drainage piping to 2" and gluing them together not using the screw type.

@Steven Darrow the market has definitely hardened and Florida is definitely its own animal due to weather vs. other markets.

Then for rentals, you would want some durability to go with affordability, so look up,  via the search function, the threads on how to harden a rental for ideas in that aspect. 

Although if there is other work going on at the house, you might consider changing it to avoid making another mess down the road, because in my experience old galvanized pipe eventually fills in with hardened substance and clogs.