# 2 Sump pumps to 1 discharge



## crcorn (Jun 13, 2010)

Both sumps are 1 1/2 '' reduced to 1 1/4" with check valves on each.
The discharge is 1 1/4", can I tee it and run both pumps at the same time?
The discharge runs about 100' to ditch.
Thanks
Mark


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## AllanJ (Nov 24, 2007)

The sump pump instructions recommend a certain pipe diameter. To run two pumps into the same pipe the diameter has to be at least 1-1/2 times that.


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## The Engineer (May 4, 2010)

If its a duplex system, (2 pumps in the same pit) is it pretty common to tie both into one discharge line the same size since they operate on a lead, lag configuration. Rarely both pumps operate at the same time on a duplex system. Now, if you have two totally seperate pumps in different pits and if they do operate at the same time, you want to upsize the discharge line so it can handle the flow from both pumps if they operate together, I would suggest a 2" pipe here. If you don't the pumps will have to work much harder to pump the same volume and they will fight against each other due to the restricted flow, and your GPM will go down about 30%. It will work, but the effeciency will be reduced.


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## a7ecorsair (Jun 1, 2010)

crcorn said:


> Both sumps are 1 1/2 '' reduced to 1 1/4" with check valves on each.
> The discharge is 1 1/4", can I tee it and run both pumps at the same time?
> The discharge runs about 100' to ditch.
> Thanks
> Mark


I'm assuming you are talking about those small submersible pumps that sit in a sump basket. Although they are plumbed with 1 1/4" pipe, the pipe isn't at capacity. I had a two sump system in my last house that I ran all in 1 1/2" PVC and it worked great.
How likely is it that both pumps will run at the same time and if they do all that will happen is the discharge will have a little higher velocity. Will the discharge from the junction of the two pumps to the drainage ditch be level or down hill?
Feed the 1 1/4" into a 1 1/2" wye, not a tee, to joint the two systems and then feed it into 1 1/2" pipe.


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