We have a two year old house. The hot water supply was OK before. I started to notice that the upstair master bathroom shower deliver less water about 2 or 3 weeks ago, but not so noticeable. At least my husband didn't notice the difference. Last week we went to a 1 week vacation. When we came back we noticed the difference right away when we took the shower. We had to turn the shower faucet to the hottest point in order to take a shower. Not mention it's impossible to use 2 shower head at the same time. Before we went to vacation we just left the water temperature to the normal setting, which is between the hot and middle. Don't know if this had something to do with the problem. Any feedback would be greatly appreciated. Thanks.

How well does the hot water work on your other fixtures. If the shower is the only problem fixture I'd inspect the hot inlet on the shower mixing valve, look for debris