the pipe connecting the two bays has a negative pitch, you need to shorten the down stem on the side that gets the backup if it is the side furthest from the drain, or get a longer stem if it is the side closest to the stem, if it is a t connection where the drain is in the middle just shorten the stem on the side that gets the backup
see a plumber
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.
If it's coming from the roof then the bathroom ceiling will have a water stain on it too. If you don't see this then it is coming from your bathroom.
That is probably the sound of water draining through a clog.
A kitchen sieve will allow this.
Call your water company to see if there is an outage or for whatever reason they may have shut it off.
water thats in the kitchen
It is already grounded through the faucet and water pipes. Even if the supply lines are PVC, it will still be grounded through the water.
You don't dumbrow water goes through cardboard
cover it
The volume of water that comes out of the tub faucet is much greater than the volume of water that comes out of the kitchen faucet. Let's say that the bathroom is twice as far from the water heater than the kitchen, so twice as much water has to be run to get the hot water. If the tub faucet allows more than twice as much water to pass through, then it will get there faster.
Since plain water is not used anywhere on a vehicle, it must be getting in through the shifter boot.