The water pressure in both my tub and my shower is lackluster. Two professional opinions suggested replacing the shower valve cartridge. I tried replacing it with both a cheap one on Amazon, and an actual Delta one from a plumbing supply store. Neither improved the issue. At one point, when the plumber removed the cartridge to "flush out the valve" I observed SIGNIFICANT water pressure coming from where the temperature lever would normally be. So I have no reason to believe that the issue lie...| Recent Questions - Home Improvement Stack Exchange