[danno331]

:confused: The existing house drain system (1950's house) has 2 drain stacks that go from basement floor and up through the roof. Sinks, showers and toilets are tied in directly to these stack/vents. The only existing re-vent is off kitchen sink and is the furthest run from where the main sewer line heads for the city connection. Is this house drain system referred to as wet venting?

Does the list below apply to wet venting and can I use the list below for installing new fixtures in basement without re-vents?

Chapter 14, Table 1409.3 of The Standard Plumbing Code, Titled "Distance of Trap to Vent"
Size of Fixture Drain in Inches Distance Trap to Vent

1 1/4------------------------------------2ft.6 in
1 1/2------------------------------------3ft.6 in
2----------------------------------------5ft.0 in
3----------------------------------------6ft.0 in
4---------------------------------------10ft.0 in

[massplumber2008]

No... that is not what is referred to as wet venting. Your system is a common waste and vent system that incorporates individual vents and wet vents for fixtures.

An individual vent is used on... well individual fixtures... and follow the maximum disatnce to trap table 1409.3 you presented. Here, if say a tub is to be installed then I must tie my vent fitting within 3'6" of the trap...then I would run that a certain length to a vent stack.

A wet vent is a vent that is run within the distances of table 1409.3 but here, for example, I might use the vent for a toilet (3" waste pipe so I must tie the 2" vent fitting to within 6 feet of the toilet) to pick up the lavatory (sink) as well...Trick here is I must run 2" all the way until it ties into the vent stack (normally a sink vent is only required to be 1.5"). This is a wet vent because when the lavatory is used the vent becomes wetted by the waste. The theory behind this is that it is rare for a toilet and a lavatory to be used simultaneously so it is valid to wet the vent in this case.

Principles of wet venting can also be applied to a tub or shower..AND a lavatory again. Only here, you would run 2" to a shower drain.. so must tie in 2" vent fitting within 5 feet of trap, run that up to sink, 2" all the way, etc.

There is a lot more to this.. but that is a basic idea for you. Any more questions.. just ask away!

Hope this helped. If it did please rate the answer below. Thank you.

[danno331]

I understand the difference, somewhat, of what wet venting is. Thank you. It almost seems any improvements should incorporate a re-vent. But to know when to re-vent and distance/size of pipe is a "black-box" of sorts. Maybe some books on the topic will help me to be more than your average village idiot. Going to the library.

No....that is not what is referred to as wet venting. Your system is a common waste and vent system that incorporates individual vents and wet vents for fixtures.

An individual vent is used on...well individual fixtures...and follow the maximum disatnce to trap table 1409.3 you presented. Here, if say a tub is to be installed then I must tie my vent fitting within 3'6" of the trap...then I would run that a certain length to a vent stack.

A wet vent is a vent that is run within the distances of table 1409.3 but here, for example, I might use the vent for a toilet (3" waste pipe so I must tie the 2" vent fitting to within 6 feet of the toilet) to pick up the lavatory (sink) as well...Trick here is I must run 2" all the way until it ties into the vent stack (normally a sink vent is only required to be 1.5"). This is a wet vent because when the lavatory is used the vent becomes wetted by the waste. The theory behind this is that it is rare for a toilet and a lavatory to be used simultaneously so it is valid to wet the vent in this case.

Principles of wet venting can also be applied to a tub or shower..AND a lavatory again. Only here, you would run 2" to a shower drain..so must tie in 2" vent fitting within 5 feet of trap, run that up to sink, 2" all the way, etc.

There is alot more to this..but that is a basic idea for you. Any more questions..just ask away!!

Hope this helped. If it did please rate the answer below. Thank you.

[massplumber2008]

Hey Danno... I am sure we can help if you want it. Tell me what your layout in basement will be like... determine fixture layout and distances from each other... AND distance from the waste line underground... OK?

You will definitely need to install individual vents to fixtures but maybe we can reduce the number needed in the bathroom (from 3 to 1, perhaps, but will need distances).

A picture would help tons... I use my paint program to draw stuff like this, then post it at "GO ADVANCED" feature on this site when posting... may need to convert file but that is also available at the post area under manage attachments... click on convert and then convert and then save converted file, and then repost it.. *whew*... but if you can get drawing to me I can design waste/vent so you can see/understand better... OK?

Glad to help. Take care.