I have a Master addition on my house that has a Master Bathroom.
Everytime you are in the master shower and someone flushes the master
toilet, the master shower scaulds the person in the shower. The
scaulding water has to be from the toilet taking too much water from
the cold water supply line. What are the obvious reasons? I think the
toilet is an old 3 gallon toilet which might consume too much water,
but are there other reasons? Is the cold water supply line to the
Master addition too small?

Any help or ideas is much appreciated!!!

Andy