Venting curious question?

[Marcus7]

So I have a 3 sinks in my home that are not vented properly only 1 has a proper p trap. The other 2 sinks are S-trapped. There truly is no venting behind walls or below.

My kitchen sink is a dual sink and that has a S-trap. It drains down vertical 2ft. into my basement then hits a 1/4th bend 90° And shoots 17.5 ft. Horizontal till it hits a long sweep 90° Back down vertical into a the ground. There is also a dishwasher hooked up to this trap and sink as well. No drainage issues.

My curious question is How do all my sinks especially my kitchen sink with such a long horizontal run have no problem draining properly. They all work pretty dang good. It’s a older home and no complaints.

I’m doing research on adding an addition to my home, and upon plumbing research I’m blown away with my setup. What am I missing because the sinks apparently aren’t plumbed right or vented right.

Thanks for any feedback just curious with this setup.

 

[Reach4]

The venting for kitchen sink drains is mainly to keep the trap from siphoning when you put a big load down the drain. You may not have high flows, or you tail the flow off to some lower flow at the end. The lower flow refills the trap.

Venting for kitchen sinks is not to make them drain better, but to avoid smells that could be caused by the trap emptying.

 

[Sponsor]

 

[Marcus7]

Thank you for the reply Reach4,

That makes sense but still Confused a bit Bc I have read numerous places and see a lot of plumbers say poor ventilation will also in most cases cause slow drainage and and gurgling along with siphoning. i Get none of these symptoms aside from a rare gurgle in a toilet once or twice a year. (Iam not disagreeing with you just wanted to point that out)

I must not have bad venting then?? But where is the venting coming from if my setup is not vented in any of the Lavsat all. The bathroom sinks could possibly be wet vented? Aside from the bathroom lavs Can the kitchen sink tie into and vent properly in any configuration from that far of a distance away? 17.5 ft.?

Thanks

 

[Reach4]

Bad venting near the fixture will never be the sole cause of slow draining of a sink or tub, I think, but if you have a belly (sag), then a proper vent may be able to work around that. For toilets, there needs to be a real path for air to move away, but that venting can be far down the path.

Bathroom sinks are not normally wet vented. They frequently wet vent other things.

I am not blessing your S-traps. But they should drain despite the deficiencies. Smell is the main deficiency.