The market is pretty dry for our budget in the area we prefer to invest in so we are considering building.

Soil is a natural filter.That gives you a very general idea of how a septic system works.  

If your bonus is dependent on how many hours you bill (and you pay for people to deliver your dry cleaning and food so you can keep billing), why would you be behind in your rent and draft letters back and forth arguing about it?

@Chris Seveney for context this would be a primary residence and house hack, so it's a little less cut and dry vs. other investment purchases I've made previously but I hear you on your analogy and POV.

De Humidifiers are more efficient for humidity and also help with the temperature "fee".  60 moist is a lot colder than 60 dry.  88 dry is a lot cooler than 88 moist.S.

Here having a dry hill to sell during really wet times is about the only way to know you'll get somewhat of a premium.

My advise, the same I gave to the OP, do a wholesale deal dry run.

If you are in a dry climate where temperatures only reach the '80s in the summer and cool off at night, then window units are only occasionally needed and sufficient.

A belly occurs when settling or compaction of the soil occurs below the pipe and causes the pipe to have a low spotwhere water can collect.

It is not nearly as cut and dry as if it were in your name and it may not be worth his time and effort to deal with it.