Re-plumbing my house in NH and wondering what the standard drain/waste pipe locations are supposed to be for kitchen sinks, bathroom vanities, toilets etc... From the research I've done I need a 3" toiliet drain, 2" reduced to 1 1/2 for the sink and tub drains, and 2" for a shower stall. What are the heights recommended for the sink drains and the distance for the toilet drain? Thanks.

Also what are the requirements for cleanouts on the 3" drain in the basement?

Hi John:

3" to toilet drain....yes.

2" reduced out of p-trap to 1.5 inch for tub

2" NOT reduced for shower p-trap

2" reduced to 1.5 " for sinks

Kitchen sink drains at about 15" to center off finish floor (to acommodate disposal).

Lavatory sink drain at 18-20" off finish floor

Toilet is 12" off rough wall to center of pipe and a minimum of 15" off side wall.

Cleanouts for 3" are required at new connection to main pipe (dandy cleanout (see pic.)), at every change of direction (within reason), at end of run, and at base of stack if going vertical waste stack.

Get back to me if need more info... Mark

Would I be safe to run 2" vents for all the drains, excluding the toilet which would be a 3" stack? Also, can I just reduce the 2" for the sinks in the wall to 1 1/2?

Very safe to run 2" vents for all drains...including toilet, except you say 3" stack vent for your application.. that is fine, too.

I wanted to add that you can run 2" drain/vent for a lavatory sink (stub out 2" to sink and then reduce to 1.5 inch pipe/trap) "as a wet vent for a toilet if the connection for sink drain made into 3" toilet drain pipe within 8 feet of the toilet... that make sense? That means that you do not have to run separate sink vent and then separate toilet vent... they can be combined.

Otherwise, add a full size 2" cleanout inline and then can reduce to 1.5" for sinks... Let me know if/when you need more.

.

I understand for the wet vent of the bathroom sink... and it will be no further than 4-5 feet from the stack so that'll work. How do you recommend venting the tub drain?

Hey John... tub being run 2" waste then reduce to 1.5" out of the ptrap to tub waste and oveflow assemnbly of tub. The vent is taken off the 2" drain line with fitting (sanitary tee) rolled above center line within 6 feet of the tub p-trap...then tub vent runs to join the other vents in bathroom.

All vents must connect...at a minimum...at least six inches higher then the flood level rim of the highest fixture in bathroom..In this case (as in most bathrooms), the highest is the sink. A 2" vent can pick up all the bathroom vents and then run that to vent stack and connect at floor above OR at existing attic vent OR out the roof 2" by itself.

Hope that made sense.

If this helped please RATE THIS ANSWER. Thnak you... Mark.

Get back with any more questions... anytime.

What do you mean by the term "rolled above center line"?

Vents need to roll above the center line of a horizontal drain line... if they rolled off drain line only at center, then when waste rolled by the stream would cover the vent fitting instead of mixing with the air from it. That make sense..

If you were to use the analogy of a clock... horizontal would be 3 or 9 o'clock. Above center line would be like 1 or 11 o'clock?

If you were to use the analogy of a clock... horizontal would be 3 or 9 o'clock. Above center line would be like 1 or 11 o'clock?
That's correct. All dry vents must be rolled upright or on a 45 degree angle when taken off the main. If this vent will be washed by a fixture, say a lavatory, then the fitting does not have to be rolled up but connects in the usual way.
Good luck, Tom

You guys have been a great help and I thank you much... so here's another question. I have 4" cast iron drain under my slab in my basement, it runs from the front where the original stack was to the rear then out to the septic tank. I am in the process of digging up the old cast iron to replace it with 4" PVC, I want to make a stack in the front and rear of the house to accommodate two separate baths. I plan on making the connection to the cast underground and tee'ing up right where it enters the foundation for the first stack, then running the PVC to the front of the house and have another 4" stack come through the floor. The stacks will be reduced to 3" for the baths and other fixtures... My question is how can I design the system so it can be pressure tested when its done? The "tee" connection will be underground approx. 1.5 feet and that seems to be the only area where you could put the plug to test the whole system. Kind of confusing?

.. My question is how can I design the system so it can be pressure tested when its done?
You don't do a pressure test on drainage. You perform a static test by capping off all fixtures , installing test or clean out tees, See image) at the base of the stacks, inserting inflatable test plugs, (see image) in the tesr tee to make the system water tight. You then take a hose up onn the roof and fill the stacks to overflowing and let them set for 8 hours before calling in a inspection. That's how we test our drainage. Good luck, Tom

Do I need to have any type of fitting such as a tee under the ground where the connection to the main drain is going to be or can I test each stack separtely?

do I need to have any type of fitting such as a tee under the ground where the connection to the main drain is going to be or can i test each stack separtely?
Since this is a remodel you don't wish to test the entire house. On each vertical stack vent before it goes under ground install a test tee and fill the stacks individually. Good luck, Tom

What about the main drain that will be buried under the floor? This will be 4" that 2 3" stacks will come off, 1 in the front and 1 in the rear.

Hi John;

When you come out of floor 4" at both stacks, install the dandy cleanout I showed you in post #3...then reduce to 3" for bathrooms. At the base of the 3" stacks, should also install 3" dandy cleanouts... unless the 4" dandys are close by then can probably use them. If any question at all.. install another cleanout... they never hurt anything and boy can they help if blockage occurs!

Also, no tee fitting off underground waste pipe... wyes.. ok, wye/1/8th bend or combination wye1/8th fitting OK... but NO TEES.. ok?

Any other questions?

I think I got it. You guys rock. Thanks a bunch.

Anytime Johnwi3

Thank you... Mark