Connecting a new bathroom to an existing drain


  #1  
Old 07-27-08, 04:43 PM
Jay-CT's Avatar
Member
Thread Starter
Join Date: Jul 2008
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Connecting a new bathroom to an existing drain

Good Day everyone,

I have 2 existing (original) bathrooms on the second floor of my home. I'll be adding a new Master Suite bathroom on the other side of one of the existing bathroom walls. I intend to utilize the existing water and septic drains for the new bathroom.

My question is this:

Is there any "rule of thumb" when it comes to adding additional plumbing or drainage? Is the existing tub drain and 3/4 inch water going to be enough for both showers? Or should I consider running a new line to the septic? My home is relatively new (1998), so most of the plumbing is sound and is mostly to code. I'm just trying to figure out a plan of action before I start tearing apart the drywall. Any advice is most appreciated.

Thanks,
Jay from CT
 
  #2  
Old 07-27-08, 05:15 PM
plumbingods's Avatar
Member
Join Date: Apr 2008
Location: Manch-vegas, New Hampshire
Posts: 1,985
Upvotes: 0
Received 0 Upvotes on 0 Posts
As far as the water piping is concerned, If you have 3/4" hot and cold lines feeding 3 bathrooms, you should be ok. Most house mains are only 3/4". If you only have 1/2" water piping, you should run new lines.

When it comes to the drainage, you can tie into a 3" PVC drain provided that you tie in downstream or upstream of the existing fixtures/drainage lines. If you tie in anyplace in between, you could affect the venting of a fixture. You will also back vent the new bathroom from the lav drains separately so you do not affect other venting.
 
  #3  
Old 07-27-08, 06:24 PM
Jay-CT's Avatar
Member
Thread Starter
Join Date: Jul 2008
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks

Mark,

Thank you. Most of this makes sense. I have 3/4 inch water lines...so I am ok there.

I don't understand the upstream/downstream idea. I will simply be adding the drain of the shower that is on the other side of the wall to the existing 3 inch line. I don't anything else shares that line.

Plan is to "T" off of the 3 inch near the tub and add the new master suite shower. I hope this will be ok.

Thanks again for the good info.
Jason
 
  #4  
Old 07-27-08, 06:36 PM
plumbingods's Avatar
Member
Join Date: Apr 2008
Location: Manch-vegas, New Hampshire
Posts: 1,985
Upvotes: 0
Received 0 Upvotes on 0 Posts
I'm sorry, I was under the assumption you were adding another complete bathroom.

If you are within 5' of the drain you tie into, you will be OK, If you are further, you will need to add a vent up into the attic and tie it into the existing vent system.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: