Gandalf in the bowels of Minis Tirinth combing through ancient scrolls to find  information on the one ring.. or.. the one deal to rule them all!

All the water issues could have caused this as well.

From there mechanical and large items are my first priority (water heater, HVAC, roof) - though an inspection gives us more information and those items can be used as great negotiation tools during your due diligence period. 

Water- Either check with neighbors, drill test well, or call me to Witch water to see if you have water on the ground. 

Then wherever the water is getting discharged off of the roof, that what water is getting at least 4-5 foot away from the structure before it is left to drain with gravity away from the property. 

Added a new cistern for water and added a shop bathroom in addition to completing the apartment.

In the desert it costs me LESS than $20 for water.

At one single family house there was an oil haot water boiler with domestic hot water.

She says that if she turns the flow low though the water does start to get warmer but it never turns hot.

Mold requires two things to grow: water and food (dust is sufficient food).