# Sump Vent



## Mech (Jan 8, 2016)

2009 IPC

Indoor sewage ejector pump pit installation

The pump is discharging through a 2" force main and the sump has a 2" vent pipe.

Can the sump vent tie into the main vent before exiting the building or must the sump have its own separate vent?  I did not see anything in the code either allowing it or prohibiting it.

If the vents can be combined, is it a bad idea to do so?

Thanks in advance.


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## steveray (Jan 8, 2016)

Pretty sure it is allowed and can't think of a reason it would be a bad idea.....As long as the vent system is sized appropriately...


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## fatboy (Jan 8, 2016)

I agree with steveray......


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## Mech (Jan 8, 2016)

I searched the internet and saw posts on a plumbing forum (not this one) saying they can be combined, other posts saying they cannot be combined, and another post saying the pump could suck the fixture traps dry if they shared a common vent system.

I know what gets posted to the internet is 100% accurate , but I wanted to double check.

Thanks again.


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## Keystone (Jan 8, 2016)

Not prohibited by code, 2009 IPC that I recall.  Take a look at the manufacturers install instructions, I have seen a separate vent specified.


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## steveray (Jan 8, 2016)

On an open vent system, it should not be possible to affect the other traps...maybe on a wet vent? But even then I can't imagine...


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## HForester (Jan 9, 2016)

Originally posted by *Mech* View Post  2009 IPC

Indoor sewage ejector pump pit installation

The pump is discharging through a 2" force main and the sump has a 2" vent pipe.

Can the sump vent tie into the main vent before exiting the building or must the sump have its own separate vent?.

 No need to have a separate vent pipe run, in my opinion. Tie it in the gravity vent system but make sure that the vent pipe all the way to the outdoors complies with Table 906.5.1. Note that Section 906.5.2 is specific about pneumatic ejectors (remember the Shone ejectors?) having a separate vent pipe. I believe that if the code meant for "pumped sumps", have an independent vent, Section 906.5.1 would have stated that. Based on my experience of watching fixtures with sewage sumps, even though the pump draw down seems fast, liquid seals in traps connected to the sump barely move. (PS- For example, a sump with only a WC connected to the sump, using the sump vent as the only vent for the WC.) It seems like these residential sewage pumps are the worse case scenario. They pump down FAST. Larger sewage sump stations seem to have slower pump down times (more volume) and thus less impact on the vent systems connected to them.


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