# Slot Width/Mesh Size + pipe size = GPM formula ?

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by stormlight, Mar 14, 2019.

1. ### stormlightNew Member

Joined:
Sep 11, 2018
Location:
CA
Hello, is there a formula to determine GPM when you know pipe size and slot size.

For example what would my GPM be with:

1 1/4 inch pipe X .006 slot size or aka 100 Mesh
1 1/4 inch pipe X .010 slot size or aka 60 Mesh
1 1/4 inch pipe X .020 slot size or aka 30 Mesh

2 inch pipe X .006 slot size or aka 100 Mesh
2 inch pipe X .010 slot size or aka 60 Mesh
2 inch pipe X .020 slot size or aka 30 Mesh

As a side question has anyone seen a .006 in a residential use?

Thanks !

2. ### MidrillerMember

Joined:
Nov 8, 2017
Occupation:
Well Driller #39-2603
Location:
Galesburg, Mi
yea we use 6 slot screen here in MI on 2" or 1-1/4" stab wells in fine sand, production is minimal but has more to do with keeping fines out than high GPM. You are missing a variable as well the formula is "Pipe size x screen slot size x screen length" but even more than that manufacturer, screen composition, gravel pack or developed. What is it that you are trying to accomplish. As a driller, the composition of the aquifer is the only determining factor in slot size. the screen can be 40' long or longer if i need the flow.
Check this out, it may or may not tell you what your looking for (also play with the calculators)

4. ### stormlightNew Member

Joined:
Sep 11, 2018
Location:
CA
Thank you,

When you say production is minimal what are you getting? Are you getting something like on the Johnson page? 8gpm for a .006 per standard screen length?

So if my goal is 16gpm and I know that the aquifer can support that, I can buy two 2 inch sand point screens at .006 connect them and drive them into the ground.

By the way are you near the lakes in Michigan ? Where are you getting fine sand? I’m in coastal CA with lots of sand.

Thanks again

5. ### stormlightNew Member

Joined:
Sep 11, 2018
Location:
CA
This is for lawn iragation by the way.

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