Some causes for a sudden water pressure drop: 1) A big leak on the main supply line. 2) one or more faucets or shower heads opened on the same water line. 3) A utility water pump failure.
With no air in the system anywhere, there would be nothing to hold pressure, so the slightest leak would cause the system to go to zero.
The simplest answer would be that the screen in the spout is clogged.
The water people turned it off incase of leaks
you have trash in your line take the shower head off and remove trash or possibly in water valve at shower
The water pressure in my house is about 140PSI. Which is definitely dangerous. It happens more often than you would think. What happens is a city will use water supply lines which are too small for the water requirements. Therefore, they have to increase the pressure. You wouldn't want a pressure relief valve, because then if the pressure was too high, it would just spray water everywhere to release the pressure. You would want a pressure regulator installed, which is what I am working on for my house right now. Just to let you know though, you may have to get a thermal expansion tank for your water heater if you don't have one. See, the new pressure regulators have a check valve in them, which prevents water from traveling back into the city pipes once it has gotten into your house. When your water heater heats the water, the air bubbles in it expand, which increases the water pressure, and will probably cause your pressure relief valve on your water heater to blow. You can get a cheap water pressure meter at any improvement store to check it out. 50-60 PSI is ok. I would say you could take it up to 70 or 80 PSI safely.
With no people being involved in any way.... a very sudden change in air-pressure - such as during a storm - might get rid of it.
It will not cause low water pressure. It will cause a loss of heated water because the heater will not be able to recover fast enough. It has nothing to do with pressure.
Sudden vasodilation
Lots of stuf can cause it including sediment or a blocked supply line
There are several possibilities. The 2 most common would be the water heater needs replacing, or you need a repipe.
I would purchase a Watt water pressure guage from your local home improvement or hardware store and check your water pressure at your faucet. If water pressure is greater than 40-45psi your regulator needs to be turned down where the water comes into the house.
A leak probably wouldn't cause a "sudden" drop in pressure. It sounds more like the system has more users than it can supply and pressure drops when someone else turns on their shower or flushes their toilet.
A leak probably wouldn't cause a "sudden" drop in pressure. It sounds more like the system has more users than it can supply and pressure drops when someone else turns on their shower or flushes their toilet.
The faucet is clogged
A clogged aerator on the end of the faucet would cause the water flow to decrease in that faucet.
Ferrous metal piping
sounds like water pump.check radiator hoses as well