Shower Flush Syndrome

As a home inspector we are asked a wide verity of questions by homeowners dealing with all aspects of their homes. The "shower flush syndrome" question is one I am asked offten.

Question:
We have lived in our four-bedroom three-bath house for three years. I love the house, but I am tired of the “shower flush syndrome”, you know when you are taking a shower and some one flushes the toilet, and the temperature changes to HOT.
Is this something that is just normal, that I have to live with?
My friend said that it could be corrected by redoing the whole plumbing system.
If there is anything that I can do please let me know.


Answer:
At the time the house is built if it is plumbed with larger pipes with enough volume and pressure many fixtures can be used at the same time without noticeable changes in water temperature, and pressure. For example only two fixtures in a bath are run on a ½ inch pipe (the smaller pipe); usually the line to the toilet, and the line for the sink. The hot and the cold for the tub and shower would be run with ¾ inch pipes (the larger pipe). With the increase in pipe size, this will help prevent drastic changes of temperature in the shower when the toilet or sink are being used.
In your case I think that the cure for the problem would be replacing your old tub and shower valve with a pressure balanced tub and shower valve. The pressure balanced tub and shower valves are single handle valve that balances the hot and cold water to try to maintain a temperature range plus or minus 2 degrees.
Call some of your local plumbing companies and compare prices.