I see a valve that says FNW on it with ( on, off ) but I'm not sure it's the main valve to the water supply. It does go to the water heater so I'm guessing that it's it. Does anyone know anything about the main water supply valve and how to find it?
Find the meter, the shut off valve will be within a foot of the meter, If the meter is digital and on the outside of the house, look for a closet, or cupboard near the meter on the inside of the house, the meter will be concealed there.. The valve you are looking at is a shut off valve for the heater.
My water hose has a valve at the base of it close to the wall, if you need to shut off the main supply to the house it is usually located in the front yard close to the street. Mine have always been enclosed in a Cement type box that is in-ground with a lid that is flush with the ground.
The main water valve is usually at the meter or front yard pipe where the hose valve is.
The valve that goes into the water heater is usually the cold water into the heater. It will shut off all the water in the house, but to make sure you should turn off the main valve. If it's an older house, this the valve into the the heater is generally the main valve, otherwise it will be located near the meter and most commonly on the house side of the meter.
