If all the fixtures-sinks,showers,washing machine etc. excluding the toilets are within 4 or 5 feet from the main 3"drain line which is attached to a 3" vertical stack,are they required to be separately vented?This scenario is existing in the plans for a slab foundation where all the plumbing is in adjacent rooms on the same level of a one level house.I do know that the toilets have to be vented individually.Would it meet the code requirement for wet venting?

Every fixture that has a trap must, by law, be vented. Let mje show you how we plumb bathrooms in my area where all the homes are on slabs. Most bathroom groups are roughed in like this.
Toilet connects to sewer main or the stack vent. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim.
More questions? I'm as close as a click. Tom

Speedball 1-how can you run the shower drain into the lavatory drain if both are not 2"lines.Usually the sink drains are 1 1/2"if that's what you mean by lavatory.I guess if you ran a 2" sink line it's possible.

You are not stating where you are located. In So. California all plumbing fixtures have to have its own, dedicated, vent. Depending on the load, vents can joint above siphon level and continue to the roof line in one pipe.

Speedball 1-how can you run the shower drain into the lavatory drain if both are not 2"lines.Usually the sink drains are 1 1/2"if that's what you mean by lavatory.I guess if you ran a 2" sink line it's possible.
You don't make ANY drainage, in new construction, 1 1/2". All drain lines should be 2" and the kitchen/ laundry drain line should increase to 3" in new construction. Regards, Tom

Cdefraia:

Like Milo asked... where are you from? There are a couple states that allow venting as you originally asked about... let us know more...

MARK

If all the fixtures-sinks,showers,washing machine etc. excluding the toilets are within 4 or 5 feet from the main 3"drain line which is attached to a 3" vertical stack,are they required to be separately vented?This scenario is existing in the plans for a slab foundation where all the plumbing is in adjacent rooms on the same level of a one level house.I do know that the toilets have to be vented individually.Would it meet the code requirement for wet venting?

Let me take this one again,
You are asking if you must run a vent if the fixture's within 5 feet of the vertical stack. This will be just dandy for the first fixture but how about the rest of them. All code stipulate that you can not discharge a major fixture past a unvented minor one. You can't just manifold them into one line and expect them to be vented just because they fall within 5 feet of a stack. If you live under UPC out in California you will be mandated to run a vent on eack fixture trap plus the toilets. But if your area allows wet venting. (check with your local building department) then follow my direction set forth in a earlier post. Good luck, Tom

As cheap as it is, it is worth venting all to make sure. Relative distance to the "stack" means nothing. One-way vents can be used inside the wall without going to the attic with it. Otherwise, you may find that flushing your toilet will suck the sink or tub trap dry, and you'll get a sewer smell in the house, play it safe, I say.

Once more I have to disagree!

One-way vents can be used inside the wall without going to the attic with it. You may not cover up a AAV inside a wall. By code they MUST be assessable to be serviced or replaced. Sorry shower guy! Tom