He refused to go check up his health for mold. 

Just make sure to consult with a couple of septic contractors as well as the local health department or environmental services division of the city or county to make sure you have all permits and fees accounted for.

A thing I’ve not done but I think has merit for risk mitigation is to own a variety of kinds of properties and own them in more than one economic region. 

it can be easier it seems to take advantage of some tax breaks if you have them, like owning your vehicle and even buying health insurance for employees if you get big enough. 

While I like not having ALL of my eggs in one basket, it is more economical to just use one basket. 

It seems like your tenant is a reasonable person who understands general economics.

It could have been some Wikipedia, some City Data, I think I looked up crime stats, also looked up some economic data for the city, county and state.

If you don’t already own your house you are probably best doing a house hack given the economics of Seattle. 

@Jay HinrichsI think it is the economics of Zillow offers that makes it interesting.   

For syndication, perhaps the rent increases weren't viable, perhaps the expense decreases work viable, perhaps there were hidden issues that couldn't be determined during due diligence, Etc.Market Risk:  Economic factors can impact any investment.