I have never dealt with any, however; have heard others that have and it seems the biggest concern these days is what environmental liability there is or could be.

Everything from zoning to environmental studies to utilities to soil tests to water management to permitting, etc.

I'm watching that with interest: http://mlf.org/community-first/Overall, I think this trend will continue because more people are seeking to downsize for cost savings, environmental benefits, etc.

There are environmental issues in every state about the concentration of these systems.

I am an engineer in training doing civil and environmental engineering on land development projects (typically subdivisions). 

That being said I did buy a house that had oil heat and I converted it to natural gas and did do environmental tests because of that.

Mike Butler from Orion Environmental.

Even if you are comfortable with the deal a commercial lender is going to want due diligence you wouldn't even think of for a SFH like a phase one environmental. etc.

This week we got under contract and have gone through environmental and mechanical due diligence - everything went well which makes me happy on the one hand but disappoints my inner negotiator who wanted some leverage on the price.  

I've just read the thread from beginning to end and it was so informative.I'd like to pick the collective BP brain if I might:I'm in the Ann Arbor, MI area and currently work full time at an environmental nonprofit.