Does a sewage pump vent need to be vented through the roof or can it be spliced into the 4" stack just before exiting the roof? I plan to revent the sink and tub with a separate vent. I have seen this question asked before with different answers.

Thanks,
Bob

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Originally Posted by boblew

Does a sewage pump vent need to be vented through the roof or can it be spliced into the 4" stack jsut before exiting the roof? I plan to revent the sink and tub with a separate vent. I have seen this question asked before with different answers.

Thanks,
Bob

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There's only one answer Bob,
The pit vent MUST BE A DEDICATED VENT. (see images) You may revent the fixture vent back into the house system but the pit vent can not be revented. The reason for this is while the lavatory and fixture vents just pull outside air into the system to relieve the suction caused by draining waste the pit vent must push air out while the fixtures are discharging into the pit it must also pull air in while the ejector pump's pumping the pit out. It's not good plumbing practice to introduce pressure into a venting system designed to operate under suction.
Run a separate vent on the pit. Good luck, Tom

Hi Tom,

Thanks for answering the question. I was afraid you were going to say that. Just out of curiosity, how can some people say that it doesn't need to go through the roof if they are going to pull a permit and have the village inspect it?

I have had a couple of quotes and both have said that sewage pit can be revented higher up without going through the roof. Also someone told me that it only had to be separate if it was a pneumatic pump.

It is just confusing that they plan to have the village inspect it if it is going to be against code.

Your thoughts?

Thanks!
Bob

You cannot connect it to the other vent system. Difference between regular vents and sewer ejector vent is that regular vents "suck" air in during flush while sewer ejector vent allows fumes to rise up by gravity to the roof. In other words, it empties sewer ejector pit of fumes. They are both called "vents" but they have different importance in the plumbing system. I hope that will explain why sewer ejector vent has to be dedicated and go all the way to the roof...

Codes vary from area to area. This is straight out of my UPC book, 2006 edition, hope it helps: 710.10, upc. Sumps and receiving tanks shall be provided with substantial covers having a bolt-and-gasket-type manhole or equivalent opening to permit access for inspection, repairs, and cleaning. The top shall be provided with a vent pipe that shall extend separately through the roof or, WHEN PERMITTED, may be combined with other vent pipes. Such vent shall be large enough to maintain atmospheric pressure within the sump under all normal operating conditions and, in no case, shall be less in size than that reququired table 7-5 for the number and type of fixtures discharging into the sump, nor less than one and one-half inches in diameter. When the foregoing requirements are met and the vent, after leaving the sump, is combined with vents from fixtures discharging into the sump, the size of the combined vent need not exceed that required for the total number of fixtures discharging into the sump. NO VENT FROM AN AIR-OPERATING SEWAGE EJECTOR SHALL COMBINE WITH OTHER VENTS.

Okay guys. Thanks for all of your help but I am ending up at the same place as when I first asked the question.

It appears that the correct way is to have a dedicated vent directly through the roof. However, it looks like some places may give a little wiggle room as long as the pump is not air operated.

I have spent the last week looking at the roofs of houses to see if I can spot two air vents instead of one. Since I have yet to see two on any roof, maybe this is one place that allows a contractor to revent higher up on a non air sewage pump. This also seems to be the only explanation that would allow the contractor to get his job passed by an inspector.

I guess I should just verify it myself with the village.

Thanks,
Bob

Yep, best to check with local authority. However, I do agree with Tom and Milo. Best plumbing practice to terminate roof separately. This way you will sleep better at night, while not worrying about whether it was done correctly or not. Good luck and please do let us know how things work out.