Homeowners wishing to enclose basement appliances should take note of air-supply requirements for both the furnace and water heater, which are powered by electricity or natural gas, oil or propane. Fuel-burning appliances use room air for combustion and require an unrestricted air supply. Any enclosure requires installation of a louvered door between living areas and the furnace room to ensure an adequate air supply and ventilation in your basement. Without sufficient air, a house may fill with dangerous gases, including carbon monoxide or radon.
Pipes will have to be brought down, and a sewage pump and backwater valve might have to be installed to ensure proper drainage of effluent and bath/shower water if gravity doesn’t work in your favor. Take care to ensure moisture prevention with a dehumidifier and vented fan system. Many building codes have minimum dimensions regarding how close each fixture can be to the next.