Question: What would cause the water pressure in only one shower go down? When we moved into this house in May, the water pressure in the upstairs bathroom was great. Over the months, the water pressure has been getting lower and lower. Even if the water is turned up all the way, it is practically worthless as a shower. The sink in that bathroom is perfectly fine, as is the toilet. The kitchen, right next to this bathroom is also just fine. The water heater is down in the basement. The shower down there is great. So what happened to the pressure in the upstairs shower? And what parts do I need to be looking at? The fixtures in there are not that old, most of that bathroom was re-done a couple years ago.