Reducing Drain Lines Before P Trap

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by AndrewK, Oct 17, 2020.

  1. AndrewK

    AndrewK New Member

    Joined:
    Apr 20, 2020
    Location:
    Minnesota
    This may seem like a crazy question. Is it ok to reduce a drain line BEFORE the p-trap? for example, a shower has a 2" Drain that is reduced down to a 1.5" pipe and then goes into a 1.5" p-trap where it continues until the building drain.

    I mean a shower or sink is almost like they're being reduced from the size of the basin to the drainpipe that leads to the p-trap already, why can't you reduce it further as long as you have an appropriately sized p-trap?
     
  2. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    The quickest answer is code it dosent meet code to reduce a shower to 1 1/2. I could tell you this and that about why I think some old guy decided this is code. but bottom line is because thats what they thought right. will a shower work on 1 1/2? yes should you break code and go small? probebly not but ive seen it many times
     
  3. Sponsor

    Sponsor Paid Advertisement

     
Similar Threads: Reducing Drain
Forum Title Date
Plumbing Forum, Professional & DIY Advice Reducing sink drain from 2" to 1.5 Jun 14, 2020
Plumbing Forum, Professional & DIY Advice reducing toilet drain Feb 16, 2006
Plumbing Forum, Professional & DIY Advice Pressure reducing valves Aug 25, 2020
Plumbing Forum, Professional & DIY Advice Reducing the outflow on a submersible pump... does it hurt the pump? Aug 14, 2020
Plumbing Forum, Professional & DIY Advice Reducing 2” to 1 1/2” kitchen pipe Jun 26, 2020

Share This Page