I'm on a slab too. I do use a back bedroom as an office and was thinking about putting some equipment and supplies in the closet. Biggest concern is a tax audit. I plan to claim a sizeable home office deduction, but hear conflicting stories on what you can keep in that room and still claim the square footage as part of the office. It would be nice to use that closet, because that wall backs to a bathroom (water supply and drain for my RO unit).I recently purchased a stenner pump to set one up. Just have to figure out how to get the lines from my water storage area to the tank. I'm on a slab so it's going to have to go through the attic!