Is it rough enough?

[Forty-Two]

Greetings!

I've lurked for a while looking for info on back outlet toilets. Our 1984 house has a laundry room (on a slab) that appears to have a roughed-in toilet/sink. We've been in the house for over eight years, and I'm finally getting a round TUIT to accomplish this addition.

Going into the crawl space, I found the following (I've attached one of the best pics, but I can go under the house for more details if needed):

A 3.5" ABS line which is clearly the laundry room toilet drain. This bends 90° (unknown radius) into a sloping main drain to which all other ABS pipes join.

After the bend, a veritcal 2.5" line (which I believe is a dedicated vent) joins the sloping main drain.

Then there is a clean-out.

Then another vertical 3.5" line joins the main drain. I assume this is the line from the second floor master bath, and the laundry room sink drains into this line.

I believe there is a vent downstream of the laundry room sink drain before it joins the second floor line, and then I think there is a vent downstream of that joining before it joins the main line.

A little bit after that on the main drain is a 2.5" line from the kitchen.

The main drain then runs a few more feet, drops a couple of feet and joins what should be the 3.5" drain from the guest bath upstairs. I assume the guest bath is complete as far as proper venting and draining. The main line then exits the house through the foundation.

Does it look like I have all proper plumbing to just add the toilet and sink in the laundry room? I think my only concern is that I might need another vent, but it really seems like it is taken care of.

I am not exactly sure how high the toilet outlet is. It's somewhere between 4" and 4.5". I am planning on the American Standard Yorkville, but any other suggestions are welcome.

Thanks!
Michael

 

[Terry]

Ok, that was getting a little confusing.

Each fixture will need it's own vent.
The fact that you have plenty of plumbing fixtures doesn't really help the new ones that you add.
Each fixture gets a vent.
Vents can be tied together 6" above the flood level.
Most plumbers just figure 42" and call it good.

The 3.5" pipes are considered 3" inside diameter pipes.
You can have up to three toilets on a 3" line, the fourth requires a 4" line.
Most homes will have 4" just outside the foundation. Sewer lines are always 4" or more.
Sometimes you have to do a little digging and bring some 4" into the home if your're planning on having more toilets.