The simplest answer would be that the screen in the spout is clogged.
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.
you have trash in your line take the shower head off and remove trash or possibly in water valve at shower
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.
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.
The most likeliest answer to this question would be that your hot water heater is unfortunately rusting or perishing from the inside, no amount of cleaning will help. your only option is to replace the hot water heater.
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.
Lots of stuf can cause it including sediment or a blocked supply line
The faucet is clogged
A clogged aerator on the end of the faucet would cause the water flow to decrease in that faucet.
THE THING THAT CAUSES YOU TO LOSE PRESSURE AND HOT WATER IS BOTH BATHROOMS ARE CONNECTED TO THE SAME LINES. SO WHEN YOU RUN SOMETHING, THEN RUN SOMETHING ON THE OTHER SIDE, YOU LOOSE POWER THAT YOU WOULD NORMALY HAVE IF ONLY ONE BATHROOM IS ON. THERE IS NO QUICK FIX, TO FIX YOU MUST REPLACE ONE OF THOSE LINES WITH NEW ONES PROBABLY FROM THE BASEMENT. ITS ALOT OF WORK, AND COSTLY. JOE HOJAS
Undo the aerator at the end of the spout and clean out the screen of the aerator. It is probably plugged up. Run the water without the aerator attached. If you have full pressure, the plugged aerator is the problem. If you do not have full pressure without the aerator on the spout, it could be plugged in the spout. Usually the aerator plugged. Cheers
A leak in the supply pipe.
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.
Low water pressure in a residential plumbing system can be caused by issues such as clogged pipes, a faulty pressure regulator, a malfunctioning water heater, or a problem with the municipal water supply.
Low water pressure in a home can be caused by various factors such as clogged pipes, a malfunctioning pressure regulator, a water leak, or issues with the municipal water supply. It is important to identify and address the specific cause in order to restore normal water pressure.
The most likely cause is a clogged aerator or faucet. Sediment or debris can accumulate and block the flow of water, causing a drop in pressure. Try cleaning or replacing the aerator to restore the water pressure.
My first thought is a leaky hot water line.