Done right, a grow op can be done with a small environmental footprint, but as @John D. points out, there are structural limitations to the house that might not allow best practices, in which case a lot of harm can be done.  

I have not increased the existing porch footprint or sq ft.

The state Department of Environmental Quality and the Oregon Health Authority plan to announce that DEQ data indicate a monthly average of 49 times the state air-safety benchmark level for the neurotoxin and carcinogen cadmium, and 159 times DEQ's air-safety goal for the carcinogen arsenic."

What is the smallest footprint that includes a functional bathroom with shower and a functional kitchenette?

I hate having to fill out information on-line..I do not like to have a cyber footprint any larger than necessary to conduct business..BUT I could not stand by and have the only comment regarding Asa & Forrest be a so opposite of what my experience has been working with these guys!

Hi Fellow Bigger Pockets Followers,As metropolitan cities experience growth patterns and changing footprints of areas of opportunities, are research must reflect that as well.

I know many of you may think how can you do that ,well fortunately  we happen to be in an extremely relaxed lending environment ,ive been in this business for 30 years and this is only the 2nd time i;ve seen real estate lending this relaxed ,for you old timers ,i know you can remember when their was no seasoning of title , in that period i was able to acquire 20 properties in 6 months ,moving right along ,heres the formula 1) find a property that needs a rehab in a b or c+ neighborhood,determine that after the rehab you will be at a 65 to 70% arv,next after you've acquired and rehabbed the property refinance it ,heres the example ,$45,000 purchase ,$30,000 rehab ,finished value $125,000,now you have a couple of options,you can refinance the property in 30 days at a 70% ltv,or you can refinance it later at an 80% ltv in 90 days,,using the example at 70% your cash out is $87,500,lets assume that your settlement costs were $8000 per transaction for the intial purchase and refinance,this equals $16,000 ,your cash out is $12,000,which leaves your out of pocket at $4000,this would be your total outlay,assuming that you rented the property and had net revenues of $500 a month your total return yearly would be $6000 monthly,your roi is 50%,now if your roi wasn't this high ,let say 30% annual return ,i don't think you would be too mad ,however you have another option and if you are not in a hurry you can refinance in 90 days at 80% ,when you refinance your cash out would be $125,000x80=$100,000-$75,000=$$25,000-$16,000 would be $9000,,so the $64,000 question would be how much did this really cost you,rinse and repeat this formula over and over  and you will be a happy camper              

I would probably avoid th ecomplications and environmental requirements of a actual marina and simply install docks for the tennats boats.

You have all outside responsibilities, the more the door opens the more often the A/C and heat kick on, the harder it works.Are there any environmental issues with these business operations?

Expect a lot more Flint Mi style demo's to reduce footprint/infrastructure requirements.How today's Bank closings compare to the 1987 era.