Grey Water Issue

[Silverman]

I'm putting in an outdoor bbq that will also have a bar with a small sink. But the sink will be VERY basic: cold water only and almost exclusively for filling cups for a quick swig of drinking water and rinsing drink cups.

There will be no actual cup washing (as in with soap), no dish washing (again, no soap, and no food particles), etc. There will be pretty much just water, ice (more water!) and some bits alcohol and juice 'runoff'. Even then, anything substantial will go in the regular sink indoors.

Knowing all this, aside from any zoning laws is there any reason I need to put this into my DWV system versus just running it into filtered gray water pit of some sort? My preference is the latter. Because of where the bbq and sink will be located, it will be far more convenient to just have it drain out into "nature". 99% of what goes out will be water and aside from some vodka or beer residue, there's not gonna be any harsh stuff coming out? And I'll be feeding into a bed mostly iceplant-type foliage... the stuff is hard to kill. And any reason I'd need a normal trap at the sink or would an elbow out to a horizontal pipe suffice?

 

[majakdragon]

Unless there are local Codes that prevent this, I see no problem. Many areas allow any water, except if it contains human waste, to be dumped on the ground. Lots of people use it for plant beds. This includes sink and washing machine water. No need for a trap since the pipe will be open on the end of the line. You may want to make a French drain with a large diameter pipe buried and filled with stone.

 

[Reedwalker]

As Majakdragon said sounds like you would be fine with a French drain or some type of drainage field.

Although I'd be careful about letting the local authorities know your plans if at all possible. You start throwing the term "Gray Water" around and it may cause you a world of trouble. A true gray water system is meant to be used as a way to recycle water back into your toilet tank.

According to the International Plumbing Code 301.3 and its Exceptions in Appendix C - Gray Water Recycling Systems; "kitchen sinks" are NOT permitted in gray water systems. I believe this is due to decaying food debris.

That said I did this exact thing you want to do for a customer of mine about 7 years ago. The inspector approved it, no hassles.