So I'm pretty confident my very low flow problems at some but not all taps in a house (hot and cold) have to do with long runs of 1/2" pipe versus 3/4 pipe elsewhere.

Is it true that replacing ANY section of 1/2 pipe with 3/4 pipe, whether at the beginning, middle, or end of the run, will improve the flow at the tap?

I read something that said flow is directly related to the overall pipe volume (circumference area and the length of the run), but that flow is not affected by where a pipe is bigger or smaller, but is a function of the overall length and the area of flow all along the length - so it doesn't matter whether you upgrade size at the beginning, middle or end of a run, the tap flow improvement will be the same. Is this true?

I am considering replacing the 1/2" exposed pipe in the house with 3/4 in an unfinished basement room before it all goes upstairs into walls...

thanks

Dan

What kind of pipe do you currently have and what's the static pressure?

It is "somewhat" true as long as the smaller pipe is a very short section.

When all is said and done, the total length of 3/4" pipe should exceed the total length of 1/2" pipe.

Completely irrelevant. If the 1/2" is 100' and the 3/4" is 200' you will NOT get any more water than if the 3/4" was 50'. All piping has a flow curve that details how much flow resistance/pressure loss occurs as the velocity increases. There is a maximum point at which the flow cannot increase without an increase in the incoming pressure, and that increase usually has to be very substantial to be effective, and at that point erosion becomes a factor.



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