We have hot water in the water heater and it gets to the washing machine in the garage, but in the bathroom farthest from the heater we are suddenly getting just lukewarm water. The entire house is only 1200 sq ft, so it doesn't have that far to go, and this is a new problem after 5 years of living here. Any ideas for what to look at?

I should add: there is no drop at all in water pressure, just the temperature, and my husband has been doing some plumbing work in the other bathroom. It seems that something must have happened in the course of the work he was doing, but we can't figure out what.

Never mind, it's a water heater issue after all...