I am installing a new bathtub that is big enough for two people. with one person leaning against each end of the tub. So I want to have the shower head in the usual position at the end of the tub, but the tub-filling spout in the center of the long side of the tub.
I'm thinking I can I just use one valve/faucet set with a diverter, like the usual setup. I'm thinking the valve/faucet should be closer to the spout. So then, the only difference (than the usual arrangement) is that the pipe from the valve to the shower will be quite a bit longer. The issue is, would the pressure drop to the shower head be such that the flow is too low ? If I understand, shower flow is limited mostly by the shower head, so if I installed a high-flow shower head, maybe I'd be ok.
But if not, if the shower flow would be too low that way, I'd consider installing two completely separate valves/faucets, one for the shower and one for the tub spout. It'd cost a bit more, but it wouldn't be that much trouble, because there are already pipes coming up along the long side of the tub, because the washing machine is on the other side of the wall.
Best Answer
Hardly any noticeable difference; though a "high flow" showerhead would make any difference WORSE, not better, as well as increasing your water use needlessly.
The water is already traveling through many feet of pipe to get to the bathroom. Whether there's 4 more feet of pipe to the showerhead or 9 more feet of pipe to the showerhead makes very little difference, particularly at the typical 2.5 GPM flow. At a more efficient 1.5 GPM flow, even less.
4 feet of 1/2" plastic pipe @2.5 gpm = 0.625 feet added head. (0.27 PSI)
9 feet of 1/2" plastic pipe @2.5 gpm = 1.406 feet added head. (0.61 PSI)
4 feet of 1/2" plastic pipe @1.5 gpm = 0.243 feet added head. (0.11 PSI)
9 feet of 1/2" plastic pipe @1.5 gpm = 0.547 feet added head. (0.23 PSI)
There's also no particular reason to put the valve set closer to the spout - so you could just put the longer pipe on the spout, and take advantage of the pipes in the shower wall.