A malfunctioning water heater can cause hot and cold water to surge through the shower heat. A faulty water pump can also cause this problem.
Because it effects the water pressure of the shower. This causes the temperature of the water in the shower to also change.
tsunami, tidal wave or a water surge.
the outlet pipe at the base of the shower has not got enough angel for the water to run free
surge tide
Incorrect pipe size installations
The storm surge.
A poor plumbing job. The pipes to the shower & sink share a pipe to the water heater and the pipe is not large enough. This causes the water pressure in the pipe to drop when the hot water is turned on at the sink while the shower is also on.
you did not pay bill
The kitchen is probably closest to the water heater and the shower is the farthest. Water cools down the farther it travels through the pipes.
Only if it is a huge surge of electrick
means you are running out of hot water
The light shines through the water