Venting toilet and shower

Hey there. I'm and experienced DIYer having completely gutted and renovated a 100 year old house. I also built a 320 sf living room addition for that same 100 year old house. Fortunately, with that house, I only replaced plumbing fixtures, so it was pretty straight forward.

Now I'm working on a different house, one built in the 50's. And I have a couple questions. I am in the process of moving the toilet in a small secondary bathroom and adding a shower where the toilet was. As it stands, the toilet is not vented, and drains straight down via a 4" cast iron pipe which T's directly into the main drain line about 5 feet below the floor in the crawl space. I plan to cut the cast iron pipe about a foot above the T, connect 3" PVC using a rubber 4x3 reducing connection sleeve, angle the 3" PVC toward the back wall, add in the toilet and shower drains, reduce to 2" PVC, and then continue up through the back wall into the attic to tie into the existing kitchen vent.

My main questions are: 1) Can the toilet and shower (within 5 feet of each other) share the same vent? 2) Does it matter which one joins the drain line first?

Here's a basic drawing of my plans. Hopefully I'm making sense. Thanks in advance for any help!

From what I can tell your drawing will be fine as long as the shower is within your trap to vent code distance.

Thanks Tom. The shower drain is 16 inches from the new vent, so that should be well within code. BTW, I really appreciate the information you guys pass along...not to mention the quick response!

The toilet MUST be below the shower connection.

hj said:

The toilet MUST be below the shower connection.

Click to expand...

Will do. Thank you, hj.