The absolute master is your main shutoff at the water supply. My home has no shower valve, my grandparent's house does as does my parents house. Neither of those valves are in the same place. Who knows what happened between the time your place was built and now? You'll need to trace the path of the pipes to know for sure.
under the sink
Gate valves used to be, now they are being superseded by ball valves.
In every home thee are a number of shut-off valves. Where the water pipe enters the house is the main shut off, usually beside the PRV, a bell shaped device for regulating the house pressure. This main cold line will then branch off to the water heater, bathrooms and kitchen. Each faucet and the water heater and the toilet will have a shut-off valve. The hot water line comes out of the top of the heater and goes to bathrooms and kitchen. Each hot faucet also has a shut-off valve under it.
There are many kinds depending on the fluid to be controlled, piping considerations, etc. Please consult google; possible search term: 'powered shut off valves'.
the disadvantages are that over a period of time gate valves seize and become in operable. also the handles of gate valves corrode quickly and gate valves don't entirely close properly making it difficult to solder. Gate valves are used for positive shut off and Gate valves are not designed for throttling like a globe pattern type . Gate valve fail because the installer has no idea what these types of valves are intended to do such as main steam shut off's or water mains..If properly used and installed correctly these valves last over 100 years under extream conditions
They provide a positive shut off and offer the least amount of resistance to flow when fully open.
An air-intake engine shut-off valve regulates air-flow to the motor, and operates as an emergency shut-off valve. There are also shut-off valves on water hoses, so shut-off valves really control the inflow of any liquid or gas.
As long as there are working valves to shut off the hose at the washing machine connection, you do not need to shut off the main. If there are no valves there or they do not work, you must shut off the main before starting and then take advantage of this time to install shutoff valves as well.
outside of the home
Tubs usually do not have shut off valve for them. You have to shut off the main supply. Depending on how the house is plumbed, you may be able to shut the cold supply to the water heater and that will shut off both the hot and cold or the main line where it comes into the house.
It doesn't need a shut off valve. In fact only Ford Motor Company installs fuel shut off valves in their cars.
Gate valves used to be, now they are being superseded by ball valves.
Closed
Closed
Closed
Closed
Closed
Closed