Nothing is draining anywhere no toilets no tubs.

Get a copy of the house drain leak check.

The challenge with disposals in rentals is they cause drain back ups and additional maintenance because people put all kinds of stuff down there!

They have to vent the drain and it's best for the draint o go into a garbage disposal so it will chop up any food

Check the condensate drain line(s). 

Does the house have a French drain system in it?

it's really easy... pretty much everything i use is either from HD - 99% or Amazon (shower trim, valve, bath fan, curtain rods, disposals, sink drains, fan timer, smoke detectors)tiles - MS international glacier or metro charcoalaccent tile - Madison Avenue Interlockingvanity - as modern looking as i can get it - vanitytub - aloha - $119kitchen kompact cabinets - usually buy the chadwood, but this was menards their other line (not good for rentals)hardwood - the stuff around $3, whatever color, but i like the natural lookpanasonic bath fans - always, always, always!

@Zachary Critchett When it comes to drain fields they need to breath and any kind of cover can not allow this to happen.

{M}IRR may only be 2-3%I concede to your point that $5K is not likely going to have Mark circling the drain ... but, in my experience, most {residential} realtors have a built-in positive bias ... so, if his realtor thinks the property is only worth $110K, there is a strong possibility the business may only be worth $100K ... or even less.Math doesn't lie ... get the actual data (2 - 3 years worth) and run a full analysis.

Put in notice that no wipes, ect are to be put in toilet and no GREASE is to be put in kitchen drains, that was our most frequent call..