Sounds like the drain guy has been out before for this issue and said it looks like the pipe was replaced but done incorrectly or incompletely.

Personally as much as you want to nt replace it unless you have it in your lease as/is there is going to be an expectation that it is repaired/replace to be brought up to the previous condition. 

If you plan to paint the entire house, the carpet will probably need replacing after that if it doesn't already.  

If you want to purchase rentals you are going to need that extra cash for an emergency fund in case you need to replace a roof or a water heater goes out, or for any vacancies because these things will happen.  

Having already been through this before I know they will hit is for missing siding, the whole said of the front building needs to be re-graded, the roof needed replacement and is causing water damage.

This site has almost completely replaced my nightly TV watching-- it's so addicting!

Replace the carpet and furnace and either replace or at least clean the duct work.  

Did you replace it?

They will have to be maintained and one day replaced. 

When I replaced mine - I went with exact same brand and tank size but a high efficiency model - measured to make sure same height - Handyman was installing - of course it didn't fit through the door where the old water heater was.High efficiency one had more insulation and about 3 inches wider.