I looked at some tub refinish kits but they are gallon size and I hesitate to get it to cover such a small area.

He and I dug the whole thing out using a 5 gallon bucket and pulling it out with a rope one bucket at a time!

You can get a 40 gallon electric Rheem water heater at Home Depot for ~$250 and installation shouldn't take your plumber very long.   

On future jobs, I plan on just getting a 5 gallon bucket, filling it with some cement, putting a 2X4 in it and mounting a motion sensor or 2, the keypad and having the base unit somewhere in the house.  

I even thought about giving each tenant their own 30 gallon trash can and let the waste disposal company pick up from each unit, thus eliminating the need for the 8yd dump.

Your sewer line can't handle a flush of 2 gallons every few hours, but can handle a shower drain that disposes of a couple gallons per minute? 

It can easily be removed with a mold removing solution or a bleach solution (1 cup of bleach, 1 gallon of water).

If you go to the grocery store to buy a $4 gallon of milk and only have $2, nobody apologizes to you.

(I put my gym membership on hold that winter).Then, I installed industrial-grade perforated pipe that was roughly 3’ diameter (the type of thing you might see kids crawling through at a playground), and three industrial-grade sump basins, each of which were 65+ gallons (large enough for a full-grown adult to crawl into).

Otherwise, if you want a green building, then get a few five gallon buckets of green paint and go to town ... it will be just as effective in raising your NOI and at least it won't cost you too much ...