Specing construction materials, furnishing and accessories?

I don't need it yet, but might want to add a garage with an accessory dwelling unit, but that's different than just a garage. 

Fannie Mae allows for accessory units in their financing.

Considering living there 2 yrs, selling and doing it again.The easy alternative is to build an accessory dwelling limit of 800sf.

A quick search also shows only 20 approved over the course of the last 10 years roughly (Although that article isnt the most accurate, as it does confuse an Accessory Dwelling Unit with the Fairfax County Affordable Dwelling Unit program. 

And then legally adding an ADU (accessory dwelling unit) or two.

. :) Are you asking as a potential landlord, a potential poolowner at your own personal residence, or as someone who wants to sell swimming pools / pool supplies / pool accessories?

It's a Single Family Residence (SFR) with an Accessory Dwelling Unit (ADU / Grandma Unit) in the back.

My roommate agreement specified things like: furnished or unfurnished, maximum occupancy- limiting number of overnight guests as it's bills paid roommate living, if it's co-ed or single sex, no smoking vaping e-cigs or substances on the property, cleaning chores/expectations, no underage drinking, pet rules, what utilities are included up to what limits and what utilities aren't included, etc.Require a security deposit from each roommate, even if small.Get a locking thermostat cover; set utility allowances so people won't take advantage of "all bills paid" rooms and have the daughter/master tenant or whoever is paying the utility bills be the person who sets the utilities.

If your configuration is such that you have 2 couples and a single occupant in your converted triplex, you may be conforming to a duplex use.Another thing to explore is an accessory unit.