You might be able to find a table somewhere that gives flow rates for pipes of various sizes and various pressures. Once you get that, you just have to convert the units.

I think you need to know the length of the pipe. The water will flow more slowly through a longer pipe, right?

If you can't find a flow rate online, I think it's possible to calculate it. You'd need someone who knows more about fluid dynamics than I do.

- Hollywood