What pressure per square inch water is. -In a typical home on city water you have a PRV set to 50-70 psi
Water pressure refers to the pressure of water in a system. In a home it will be 30-50 psi typically and this is governed by the municipal pressure or by a well tank.
pressure difference
My guess is that the hot water heater is installed downstream from a pressure reducer to limit the maximum water pressure that the water heater is exposed to.
An indication of the test pressure in terms of water depth does not mean a water,
If you are on a well it means you have a problem in the pressure tank. On city water means pressure in general is down, or your PRV is failing.
If you mean a well tank, the water is forced in by the pump. The residual air pressure pushes the water out to the faucets.
when the water pressure is low in the shower
Water, like any fluid, flows from where its pressure is higher to where its lower.
What do you mean by bad? Bad water pressure? Bad water?
If you mean to ask if cold bodies of water are associated with high or low atmospheric pressure, they aren't. Atmospheric pressure can change independently of the temperature of bodies of water.
The cold water inlet valve to the water heater is closed.
when water vapour condenses and forms clouds whichthen produces an air pressure which produces precipitation like a water cycle.