In a modern, one-handle tub/shower fixture with a diverter, is the flow restriction typically applied in the mixer or at the faucet and showerhead? We have what feels like lousy pressure in our shower, but I’ve measured the flow at about 2.5 GPM, which I understand is pretty standard. A half bath on the same level of the house, however, has over 6 GPM flow at the (older) sink faucet — and I’d like to try and get a similar rate going in the main bathroom. Any advice?
Could be something as simple as calcium or some other kind of buildup in the shower head screen. If the flow is as slow coming out of the spout too though then I’d say there’s a blockage or buildup in the shower valve itself (or a tore up washer of some kind partially blocking flow). Take off the shower head and clean the screen and all thoroughly and replace, and if not that then I’d take the valve stem out and clean the valve up internally if possible and check for loose/broken washers, o-rings, etc.
I had the same problem. Took the whole showerhead off, and in the top where it threads to the extension tube, there was an orifice plate with a very small hole in it, (less than 1/8 inch). Probably there to meet the 2.5 gallon requirement. Oddly enough, it had a cross in it, just like a philips screwdriver. Took it out, much better.