[Bjorn]

I have a "whole house" filter in my Utility room , that I change out 2 to 3 times a year...lots of sediment....
old rusty pipes and sediment....

glad you found the problem.....
usually I can tell when our filter gets to the change time...if we run both showers , "normally" its ok , when second shower trickles if first is on , time to change filter out.