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Old 01-03-2013, 03:43 PM   #1
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3/4" vs 1"

I found out that my main water line coming into my house is 3/4". I had already bought 1" pipe so I put a converter from 3/4" to 1" and ran the lines to my water heater, whole house sediment filter and water softener which all have 1" direct lines in. It then goes into all 3/4" pipes from there. My question is: Should I remove all of the 1" pipe? I've been told that going from a smaller pipe to a larger pipe decreases pressure, but I've also had a plumber tell me that running 3/4" pipe throughout my house (that replaced 1/2") is much better because it's not all about pressure, but volume as well. My water pressure is ok, but not great (probably due to my water softener and sediment filter). I'm on a community well of about 15 houses. Is there going to be a benefit or will I see a difference positively if I switch to all 3/4" pipes? Any help would be greatly appreciated!


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Old 01-03-2013, 04:39 PM   #2
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It will not affect pressure.....the only time the pressure will drop is when you have flow....but since it all goes back down to 3/4", net result is the same....if anything, it will improve pressure because your flow losses through the 1" section will be less than through the equivelant 3/4" pipe.

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Old 01-03-2013, 04:55 PM   #3
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IMO you're better off with 1" because of the restriction from the treatment equipment.
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Old 01-03-2013, 07:17 PM   #4
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Everything comes out your fixtures at 1/2" or less (down to 1/4"). So I'll let a plumber correct me if I'm wrong, but I don't see how any intermediate increase in pipe size could possibly decrease pressure at your fixtures.

Think of a river that flows into a lake, and there is another river of the same size flowing out of the lake at the other end. The flow of each river is going to be the same.
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