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supply line sizing

I currently had the pleasure of troubleshooting my water supply system. After replacing the well tank, pressure gauge, and various fitting due to an unexpected cold snap, i noticed that my supply line from my well to the house is 1" PVC all the way and doesn't reduce to 3/4" PVC until just before it enters the house (distance of around 156'). My water pressure has been marginal before and after the tank change and i was wondering if it could be because the line doesn't reduce down to 3/4" PVC somewhere other than right before it reaches the house connection (mobile home)? I know that 1" PVC will carry a higher volume of water, but i'm also thinking that reducing it down one size would help the pressure increase to my fixtures?

Re: supply line sizing

Reducing your line from 1" to 3/4" will not get you higher pressure.

Re: supply line sizing

On a well system the pump on/off pressure switch is what determines the pressure. They are adjustable.


Re: supply line sizing

Static pressure is not related to pipe size, but flow rates are. Unless it's been changed, older mobile homes often used 1/2" piping throughout, and that is inadequate. Even newer ones with 3/4" where it's needed are restricted by the types of fittings used which are closer to 1/2'" internally than 3/4". And the fixture faucets are all plumbed with 3/8" internally. Plus they don't take overpressure well at all. Take a pressure reading as close to where the main enters as you can- you should be seeing between 60-80psi there. If not check at the well outlet. If it's the same raise the well pump pressure. If it's OK at the pump but not at the house, you've got a blockage in the main line.

If you really want to avoid problems in the future and get better water flow, yank out all the gray stuff and replumb the whole place with PEX. You're going to have to cut out the insulation board from underneath to do this- just be sure to replace it using screwed in 3/4" wooden scabs and seal it with real duct tape (the shiny kind with peel off backing) when you're finished. Mobile homes aren't all bad, but their plumbing is universally horrible.


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