# sink drain/traps **URL:** \ **Category:** Plumbing Inspections\ **Created:** [June 15, 2012, 7:24pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902 "2012-06-15T19:24:09Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![dokeefe](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dokeefe/32/171355_2.png) [@dokeefe](https://forum.nachi.org/u/dokeefe)\ **Post date:** [June 15, 2012, 7:24pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/1 "2012-06-15T19:24:09Z")
A little help here would be appreciated. This is new construction, under the kitchen sink. I’m not sure if this is OK. It looks a little hap hazard, not neat, (two traps?) especially for new construction. anytime I see work like this I start to question it. Thanks for any help. ![033.jpg](https://global.discourse-cdn.com/internachi/original/3X/7/1/710cbdbc98a6c8723f3c23a7cd0e6aec9449a8d8.jpeg) ![032.jpg](https://global.discourse-cdn.com/internachi/original/3X/9/d/9dbbe4c3c93d13bb307b9fdc0bce897061b6d39f.jpeg) ---
**Author:** ![dokeefe](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dokeefe/32/171355_2.png) [@dokeefe](https://forum.nachi.org/u/dokeefe)\ **Post date:** [June 15, 2012, 7:28pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/2 "2012-06-15T19:28:09Z")
I was thinking this is some type of temporary setup. that adding a disposal would clean this up. any thoughts? ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 7:52pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/3 "2012-06-15T19:52:09Z")
Not allowed… Only one P-trap allowed for each horizontal run of drain to the stack. Also… the high loop needs to be properly secured in the proper position. ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 7:53pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/4 "2012-06-15T19:53:11Z")
> [@dokeefe](#): > > I was thinking this is some type of temporary setup. that adding a disposal would clean this up. any thoughts? Depends how the disposal is installed. ---
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [June 15, 2012, 8:33pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/5 "2012-06-15T20:33:41Z")
improper double trap noted. Fixtures must not be double-trapped because of the unnecessary additional restriction of flow and the increased potential for stoppages. Double-trapping can cause air to be trapped between the two trap seals, and the “air-bound” drain will block flow. ---
**Author:** ![dokeefe](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dokeefe/32/171355_2.png) [@dokeefe](https://forum.nachi.org/u/dokeefe)\ **Post date:** [June 15, 2012, 8:41pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/6 "2012-06-15T20:41:39Z")
> [@jjonas](#): > > Depends how the disposal is installed. I was thinking installing a disposal would eliminate one of the traps. ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 8:44pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/7 "2012-06-15T20:44:34Z")
> [@dokeefe](#): > > I was thinking installing a disposal would eliminate one of the traps. Only if they plumbed it correctly while installing the disposal, which would mean re-doing everything already in place. I have seen many that were not. ---
**Author:** ![jfunderburk](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfunderburk/32/187920_2.png) [@jfunderburk](https://forum.nachi.org/u/jfunderburk)\ **Post date:** [June 15, 2012, 8:46pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/8 "2012-06-15T20:46:10Z")
I don’t see that as a problem. Here is a similar thread: [http://www.nachi.org/forum/f22/double-trapped-22365/](http://www.nachi.org/forum/f22/double-trapped-22365/) ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 8:47pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/9 "2012-06-15T20:47:30Z")
> [@dmacy](#): > > improper double trap noted. Fixtures must not be double-trapped because of the unnecessary additional restriction of flow and the increased potential for stoppages. Double-trapping can cause air to be trapped between the two trap seals, and the “air-bound” drain will block flow. Actually… double trapping can cause one of the traps to siphon out and break the seal, leaving it unsealed. ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 8:49pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/10 "2012-06-15T20:49:19Z")
> [@jfunderburk](#): > > I don’t see that as a problem. Here is a similar thread: [Double Trapped? - Plumbing Inspections - InterNACHI®️ Forum](http://www.nachi.org/forum/f22/double-trapped-22365/) [http://www.nachi.org/forum/attachments/f22/15899d1194620507t-double-trapped-pa270034.jpg](http://www.nachi.org/forum/attachments/f22/15899d1194620507-double-trapped-pa270034.jpg) Flow from the disposal drain can cause a siphon in the sink trap, emptying the trap and breaking the seal… or vice-versa. (Especially with the dishwasher discharge flow rate & duration). ---
**Author:** ![jfunderburk](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfunderburk/32/187920_2.png) [@jfunderburk](https://forum.nachi.org/u/jfunderburk)\ **Post date:** [June 15, 2012, 8:50pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/11 "2012-06-15T20:50:59Z")
Here’s a double trap: > **[InterNACHI®️ Forum](https://forum.nachi.org/)** > > The InterNACHI®️ forum is a place for home inspectors and InterNACHI®️ members to discuss everything and anything related to the home inspection industry. ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 8:52pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/12 "2012-06-15T20:52:41Z")
Same principle, different hook-up. ---
**Author:** ![jpope](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jpope/32/59425_2.png) [@jpope](https://forum.nachi.org/u/jpope)\ **Post date:** [June 15, 2012, 8:55pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/13 "2012-06-15T20:55:17Z")
Not allowed by UPC standards. What code does your jurisdiction follow? ---
**Author:** ![jfunderburk](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfunderburk/32/187920_2.png) [@jfunderburk](https://forum.nachi.org/u/jfunderburk)\ **Post date:** [June 15, 2012, 8:57pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/14 "2012-06-15T20:57:55Z")
> [@jjonas](#): > > Flow from the disposal drain can cause a siphon in the sink trap, emptying the trap and breaking the seal… or vice-versa. (Especially with the dishwasher discharge flow rate & duration). An S-trap has the siphoning problems you mention. The problem with a double-trap is that air gets trapped \*between \*the two traps and will cause a stoppage of flow or blockage. I don’t see any way air can be trapped between the two traps in the OP’s picture. ---
**Author:** ![dokeefe](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dokeefe/32/171355_2.png) [@dokeefe](https://forum.nachi.org/u/dokeefe)\ **Post date:** [June 15, 2012, 9:25pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/15 "2012-06-15T21:25:12Z")
> [@jpope](#): > > Not allowed by UPC standards. What code does your jurisdiction follow? We follow the IRC ---
**Author:** ![jjonas](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jjonas/32/301755_2.png) [@jjonas](https://forum.nachi.org/u/jjonas)\ **Post date:** [June 15, 2012, 9:30pm UTC](https://forum.nachi.org/t/sink-drain-traps/69902/16 "2012-06-15T21:30:36Z")
> [@dokeefe](#): > > We follow the IRC And this is where you need to decide which road your company will take. If there is a potential risk for anything to go wrong, that is the road I will take. My clients health/safety is at risk. I will not ever knowingly place a client at risk, no matter how irrelevent it may seem to others. My clients, my company, my decision! ---
**Author:** ![dokeefe](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dokeefe/32/171355_2.png) [@dokeefe](https://forum.nachi.org/u/dokeefe)\ **Post date:** [June 16, 2012, 11:59am UTC](https://forum.nachi.org/t/sink-drain-traps/69902/17 "2012-06-16T11:59:22Z")
Thanks for your help. I added it to the report.