Old 08-31-2011, 02:26 PM
Senior MemberCaptains Club Member
Join Date: Mar 2005
Location: Boat,Town Cove, Cape Cod. Live south of Boston.
Posts: 1,479

The key is the velocity of the water, the larger 1 1/4 will lower the velocity and the pressure drop at fixtures in the house, say your useing 8 gpm, the flow through the 3/4 & 1 1/4 is going to be the same but the velocity, rate of flow through the 3/4 is going to be higher/faster than the 1 1/4. Hope this helps.
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