Bathtub water flow rate question

[texcollins]

I need to put a faucet valve in my bathtub and have been presented with two choices, either a 14.9 GPM@45 PSI or a 7.2 GPM@45 PSI. Can anyone tell me what a standard bathtub flow rate is? There is about $150 difference between the two choices and I'm wondering the flow rate in a typical bathtub is so I might have an idea how to compare. Thanks!

[jimbo]

One question would be what size pipe you have feeding the tub, and at what length from the main/water heater. 1/2 inch pipe will not deliver 14 GPM, without way too much pressure drop. You would have a water velocity of 14 feet per minute ( way too much ) and a pressure drop of 22 psi in 40 feet.

[jadnashua]

As noted, the biggest thing is what size are your supply lines? My guess is that the higher flow rated one expects 3/4" supply lines, and you won't get that flow unless they are that big.

[Redwood]

The larger flow tub fillers are primarily for large tubs. Yes the supply would have to be there.