Confused about the 10 foot head DWV test

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I am running all drain the lines from a new first floor addition over and through the existing foundation wall, and to the stack in the unfinished basement; sink, shower, and toilet. I am running the vent lines through my cape cod's front knee wall, above the stairs, and tying it into the existing vent at the top of the stack. This is located in the existing finished house's attic.

I am not entirely clear on how high I have to fill the system with water. 10 feet above the highest fixture's trap? 10 feet above the final vent fitting, which would mean 10 feet above where it ties into the stack in the attic? Overflow the existing vent pipe out of the roof? I may opt opt for a negative pressure test with a shop-vac if I need to fill the new vent lines with water, just in case there IS a leak above the existing living space.
 

Kreemoweet

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It means 10 feet of water above any piping that is meant to be under test, plain and simple. I've seen plumbers temporarily attaching
a 10-ft stick of pipe (can be any size) above the roof vents to make sure their test was all copacetic. I've heard a lot of inspectors will not be so demanding, especially in regard to vent-only piping.

I don't believe there's any such thing as a "negative pressure" test.
 

Sylvan

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What the inspector is looking for integrity at a 5 PSI test. Actual hydrostatic pressure is .433
 

John Gayewski

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It sounds like your current plan may not be to code if you care. Tying into your existing bathroom might cause you some problems on the existing bathroom if it's been wet vented. Be sure the fixtures on your basement bathroom are individually vented before you tie in upstream.
 

Jeff H Young

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tying a new bathroom into the main stack in basement dosent indicate to me he has plumbed anything wrong though its posible he has done so He could have done many things wrong but nothing in his post puts reason to belive he hooked anything up wrong .
A lot of times the inspector basicaly is concerned that the pipes are filled up through the top plates of wall and not overly worried about the vents in attic but those too should have water but being 10 feet above the highest joint in the attic I never heard of
 
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It sounds like your current plan may not be to code if you care. Tying into your existing bathroom might cause you some problems on the existing bathroom if it's been wet vented. Be sure the fixtures on your basement bathroom are individually vented before you tie in upstream.
I am only tying the new vent to the top of the stack, where the current vents enter the stack.
 

Jeff H Young

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I think that was clear Most inspectors would be ok filling it to the connection perhaps even befor they were joined
I just thought of a perfect way except that you nned to go on the roof .
1 Complete the vent connection 2 plug up drains to addition only 3 Drop a test weenie down the 4 inch vent pipe from above with extention hose (you must be below the tie in ) 4 secure weenie so it cant drop down stack 5 fill with water till it soills out at roof.
Sorry I over looked how easy this would be
 

John Gayewski

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I am running all drain the lines from a new first floor addition over and through the existing foundation wall, and to the stack in the unfinished basement; sink, shower, and toilet.
If your tying your drains into a system that is wet vented then it's not ok.

The way this is worded is very much not clear. Are there fixtures in your unfinished basement? Is there a sink, shower, and toilet in your basement or not? If not your OK, if there is then those fixtures need to be individually vented.
 
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If your tying your drains into a system that is wet vented then it's not ok.

The way this is worded is very much not clear. Are there fixtures in your unfinished basement? Is there a sink, shower, and toilet in your basement or not? If not your OK, if there is then those fixtures need to be individually vented.
Oh no. Nothing in the basement. Each fixture in the new addition will be vented then joined and carried out to the top of the main stack in the attic. The drain lines will then join the main stack in the basement.
 
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Brian Did you figure out how to test it?
I have not yet. I am going to have to call the inspector again to clarify. I will update when I do. He did tell me that many opt for some shop-vac test instead these days. I am assuming that covers scenarios like mine where the new vent pipe goes over existing living spaces.
 

Jeff H Young

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If You dont have a test weenie to put down the vent stack here is another easy way.
Presumeably below the 4x4x2 santee in vent stack about 4 inches put a shielded 4 inch pvc coupling over the pipe put some plastic sheeting tighten clamp fill with water through roof easy as pie
 
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I spoke with the inspector today. I would indeed have to test above the highest vent fitting, but he would be okay to have water just out the top of the existing roof termination of the stack. Since I don't want to fill those vent pipes with water and risk leaking into my existing interior, I am opting to perform the vacuum test with a shop-vac. I just need to figure out how to hook up the vacuum gauge and the shop-vac to a ball gauge. They want to see the pressure drop, then hold with the shop-vac off for 15/30 minutes.
 

Jeff H Young

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Im not getting isnt it just a 4 inch vent with a 4x2 san tee just below the roof with no other old pipes being tested? what is the scare with the vent pipe?
 
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Im not getting isnt it just a 4 inch vent with a 4x2 san tee just below the roof with no other old pipes being tested? what is the scare with the vent pipe?
The new vent pipe will run into the attic above the existing living area. If I have a leak during testing, it would ruin the drywall in those rooms. Instead of penetrating the roof for the new addition, I am running the vents up to where the existing vents are tying in to the stack.
 

Jeff H Young

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The new vent pipe will run into the attic above the existing living area. If I have a leak during testing, it would ruin the drywall in those rooms. Instead of penetrating the roof for the new addition, I am running the vents up to where the existing vents are tying in to the stack.
Ok well Im never concerned with the vent pipe leaking Ive had cookies and dollar plugs blow off on w/c and shower drains but the vent pisses out a cup of water you just drain system back down . You surely didnt burry all your pipes where they arent visable befor inspection I hope any way good luck with test and inspector!
 
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Ok well Im never concerned with the vent pipe leaking Ive had cookies and dollar plugs blow off on w/c and shower drains but the vent pisses out a cup of water you just drain system back down . You surely didnt burry all your pipes where they arent visable befor inspection I hope any way good luck with test and inspector!
Nah. All is good. I am just concerned that IF there is a leak, I would have drywall repairs to most likely do.
 
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