I'm installing a new shower in a cottage bathroom. THere was no previous shower. I plan to use the same vent that I use for the toilet and sink. The shower is around 10 feet from the vent; the toilet and sink are between the shower and vent. Is it possible for the vent to suck all the water out of the S trap of my sink? I want to know if I should be installing a vent closer to my shower, but this could be tricky. Thanks for any help.
Danny

Yes, flow of waste water through your drains can siphon water out of your sink trap...

I plan to use the same vent that I use for the toilet and sink. Here you tell us that both toilet and lavatory are vented and here you say it is n't,
Is it possible for the vent to suck all the water out of the S trap of my sink?

If the sink has a "S" trap then it isn't vented so where's this vent you speak of? Something's not adding up here. Regards, Tom

Yes, flow of waste water through your drains can siphon water out of your sink trap ....

Will it happen in this case? I have the toilet with the main stack behind it. Then I have a sink with a vent attached to the stack. I'm installing a shower on the other side of the sink, and planned to use the same drain. (no new vent) Would this work, or would it siphon the water from my sink?

Here you tell us that both toilet and lavatory are vented and here you say it is n't,
If the sink has a "S" trap then it isn't vented so where's this vent you speak of? Something's not adding up here. Regards, Tom

We have main stack behind toilet, vented sink--yes there is an S trap and shower not installed. The shower uses the same drain, so is only vented through the sink. I'm debating if I need a separate vent for the shower.