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New Member

Posts: 3

Location: USA


Friday, May 4th 2007, 8:35am

Initial hookup

I have a well and septic system. I have a 1" PVC coming into my basement into a pressure tank from where it's converted to 3/4" and goes up to house plumbing.

Question: Do I just continue to use a new 3/4" main line outside and install backflow preventer, valves etc... or do I install a 1" main line (about 30'to 40')just after the pressure tank where it is 3/4", run it outside, install backflow then valves (which I noticed most are 1")and then run my 3/4" lateral pipes?

I would assume the 2nd option would be the way to go but I'm not sure what would happen to the pressure if I install 1" pipe after the 3/4" in the basement after the pressure tank and then back to 3/4" for laterals. On second note, is it safe or wise to install the main line right off the 1" PVC coming from the well before it hits the pressure tank? Any advice appreciated - familyguy


Supreme Member


Saturday, May 5th 2007, 4:41am

Use at least 1" pipe. If your mainline is a long run and/or your projected flow is going to exceed 12 gpm it may be wise to use 1.25"


Advanced Member


Sunday, May 6th 2007, 3:47pm

yeah when in doubt go up to the next size..


New Member

Posts: 3

Location: USA


Monday, May 7th 2007, 5:12am

Thanks for the advice so far guys, so then it's OK to connect a 1" pipe to my existing 3/4" AFTER the pressure tank? No isues with pressure dropping or anything like that? I did not do the "bucket test", but measured in PSI at the front spigot-came to 40psi when full open. Working through some of the Design Capacity charts(Hunter), I should be right around 8gpm and 30psi working pressure. So let me know if this sounds right: Cut into my existing 3/4" after pressure tank with 1" PVC and run it outside. Install Backflow preventer, then Valves. From here, do a reducing coupler back to 3/4" for the lateral pipes to sprinkler heads. Right? Question on backflow - can I use a PVB. Do I use both, or just one or the other?

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