The NEC, or the National Electric Code, requires that all dwelling units install a GFCI for single phase, 125-volt, 15 and 20 amperage receptacles used in the following rooms:
Kitchens: Receptacles supplying countertop areas, dishwashers, and all receptacles in a 1 to 6 feet distance of a sink.
Bathrooms: Every receptacle in a bathroom space.
Garages/Sheds: Floors meeting and below grade level, non-living areas, storage, work, and task areas.
Outdoors: Electrical devices and receptacles on the outside of a structure must be GFI protected. This is unless the receptacle is not easily accessed and/or supplied energy through a branch circuit for floor-based de-icing or snow melting electrical devices.
Unfinished basements and Crawl Spaces: Non-living spaces, storage and work. This also applies to space at or below grade level.
*However, exceptions are made when receptacles solely support a permanent fire or security system, outlets not easily accessible, and on outlets noted for plug-in use only or on branch circuit system.
Laundry/Wet Bar Sinks/Utility Areas: Any electrical outlets placed in a 6 feet radius of the sink.
Pool and Spa Spaces: All electrical outlets, receptacles up to 20 feet away from the water source, pool cover power source, and pump receptacles.