Reverse osmosis filter apparatus having a reverse osmosis filter system, a pan connected to the reverse osmosis filter system and located at the bottom thereof to collect water that leaks from the reverse osmosis filter system and a water sensing shut-off valve connected to the pan, the water sensing shut-off valve being coupled between a raw water input and the reverse osmosis filter system, the water sensing shut-off valve being connected to the pan at a location to sense the presence of water collecting in the pan and to disconnect the reverse osmosis filter system from the raw water input when the presence of water is sensed. Various features and embodiments are disclosed.