I just replaced a 2nd bathroom and put in all new copper pipes in that bathroom. Sense doing this job the water pressure in my upstairs shower as changed, but only when you flush a toilet or turn on another water source. This didn't happen before, why all of a sudden the drop in pressure? Can this be fixed?

Many thanks:o

I guess the supply pipes are too small to handle the additional load - that is, when more that one fixture is being used at once. Ideally, you could do a repipe job, but that would be an expensive pain-in-the-@$$.

Moishe

This is what I do not understand though. I had a bathroom in place already with existing pipes. Everything worked fine. You where able to have the washer going, washing dishes and take a shower at the same time with no noticeable pressure issues. Why, now all of a sudden after replacing a few pipes I can see a noticeable change in water pressure when more than one water activity is going on? It doesn't matter what the combination, there is now a noticeable pressure change.
My water heater is about 11 years old and needs to be replaced. I know the house only had 1 1/2 bath when originally built. Could it be that the water heater is too small or too old? It is a 65 to 75 gallon gas water heater. Would the water heater have anything to do with this issue?

Thanks

More likely than anything else you knocked some crud loose and it is lodged somewhere blocking the shower. If you are lucky it is right at the shower and can be flushed out by removing the cartridge and briefly turning the water back on.

... and it's not the water heater being too small - if that were the case, you'd simply run out of hot water quicker; the pressure would still be the same.

Moshie and labman both hit the nail on the head. You have a volume problem caused by attaching too many fixtures on a 1/2" branch, too small pipes in the system to carry the load or crud blocking the flow. Your water heater is abover the average size of 40 gals so that should not be a probloem. Regards. Tom