Seeking clarification on venting requirements.

[Tlhfirelion]

Hey guys, first off Happy Easter. I'm planning to move my washer/dryer to my basement. I have a good spot right by the water heater and supply lines. From researching on here it seems a Zoeller pump set up with a utility sink might be my best choice. I also read Liberty is a viable option. Washer drains Into sink, sink drains into above ground sump pump, thru check valve and up and out. If that's not correct so far, please steer me right.

Now, where I run into a wall mentally is the drain/venting needs. Right above my water heater and planned washer/dryer location is the master bath. There is a roof vent attached to something in this bathroom, the toilet drain? (I think). I live out in the country in Missouri so building codes are not anything like other cities and states. No permit is needed (I checked) but I still want to do this right.

I thought I could run up 5-6' and tap into the line you see in the pic attached, add a P trap there and be golden, but a search left me confused. Any clarification on this would be greatly appreciated.

Thank you.

 

[Cacher_Chick]

If you are planning to tie into an existing vent, the connection must be made above the other fixtures, or more specifically, at least 42" above the floor on which those fixtures are located. More often than not, it will be easier to run a new vent straight up through the roof. You can also to the vents together in the attic, if it is accessible.

The fixture(s) need traps. There is no trap on the pumped line.

 

[Sponsor]

 

[Tlhfirelion]

If you are planning to tie into an existing vent, the connection must be made above the other fixtures, or more specifically, at least 42" above the floor on which those fixtures are located. More often than not, it will be easier to run a new vent straight up through the roof. You can also to the vents together in the attic, if it is accessible.

The fixture(s) need traps. There is no trap on the pumped line.

Thank you for the reply. I'm thinking I should just go thru the wall to the right of the water heater and try and tap into the drain that goes up to where the laundry is now. What's there has worked so maybe that's what I should do?

 

[Jadnashua]

No, you're missing the point! Once a drain, always a drain. IOW, you cannot use an existing drain pipe as a vent. THey got away with it a long time ago because they tended to have a quite large main drain line, and it was not likely the flow would cause other p-traps to be siphoned. TOday, the plumbing fixtures can be spread out across the whole house, and siphoning is a major problem if not vented properly. The purpose of the vent is to prevent flow from other drains from siphoning a p-trap dry. A dry p-trap is an open path to the sewer. The issue with an s-trap is first, no vent, and second, it can tend to flow too well, and siphon itself dry.

 

[Tlhfirelion]

No, you're missing the point! Once a drain, always a drain. IOW, you cannot use an existing drain pipe as a vent. THey got away with it a long time ago because they tended to have a quite large main drain line, and it was not likely the flow would cause other p-traps to be siphoned. TOday, the plumbing fixtures can be spread out across the whole house, and siphoning is a major problem if not vented properly. The purpose of the vent is to prevent flow from other drains from siphoning a p-trap dry. A dry p-trap is an open path to the sewer. The issue with an s-trap is first, no vent, and second, it can tend to flow too well, and siphon itself dry.

I don't think I explained my last post well. Currently where the washer and dryer are located is your standard hot and cold water supply and a wall drain for the washer. What I was considering is using that SAME SUPPLY LINES AND DRAIN just access it in the crawl space 4' below where it currently is. As far as the drain goes, This is before any traps, elbows, etc, just below the interior wall opening on the main level.

Hopefully that clarifies what I said earlier and would qualify under your "once a drain always a drain" statement. If it's worked for this long with no issue, why would accessing it slightly lower before any traps be an issue?

I reread your statement above and honestly, I'm confused still. My main drain is a 6-8" pipe. The house is 30 years old. Sorry for the confusion, I know this is baby stuff to you guys. I appreciate your feedback.

 

[Cacher_Chick]

If you use a washer standpipe, the trap must be above the floor, and it must be vented. If you use a laundry sink, it must have a trap and that trap must be vented. If you install a basin & pump system, the basin must be vented. The vent for any or all of these must be a dry vent which goes up and out through the roof.

Cutting in a the new drain connection for a pumped basin will require you to install a wye in your existing building drain. This wye should be downstream of the other fixture connections to the drain.

 

[Jadnashua]

What you may have had before, essentially no vent, will NOT pass code today, and any inspector will give you grief. The line going up is a drain from above, so it cannot be used as a vent. Now, as it progresses up through the house, it may actually eventually become the house vent, but that would be once the pipe was above the highest drain inlet to it. TO create a new vent for the WM, you need to run a new pipe as a vent up, above where that pipe is used as a drain, to the magic numbers of 42" above the floor of that drain, OR 6" above the flood rim of the highest drain fixture (typically that would be a sink rim), whichever is higher. Often, it's much easier to connect in the attic, or just make a new penetration through the roof.