[PedroBurro]

Do I need to connect the dishwasher drain to my sink, or can I hook it to the main drain of my house? The distance from the dishwasher to the sink is more than the 10ft limit imposed by most major dishwasher brands. If I connected to the main drain of the house, the pipes would go down the entire way.

Thanks!

[massplumber2008]

Hi Pedro

You can bypass the sink drain and connect into the main waste line ONLY if you plan to install a PTRAP and a VENT.

For a quick installation you can hook into the main drain and then install a PTRAP and a mechanical vent (called an AAV)... see image. These AAVs are not code legal in most areas. You would pipe it up much like the picture below and you would only need to install 1.5" pipe/trap/AAV (the standpipe could be 24").

Otherwise, you'd need to install the PTRAP and run an 1.5" vent to the nearest vent in the house... can be quite a project!

You could also pipe this up to the existing sink drain by looping the dishwasher drain hose up high under the countertop and pitching it back toward the sink drain... works just fine for most applications like this.

Questions? Let us know...

Mark

[PedroBurro]

Thanks for your help Mark. A follow-up question: how firm is the 10ft length limit that most dishwasher manufacturers set for dishwasher drain lines? Would it be up to code to go beyond that length?

[massplumber2008]

I think the 10 foot number is a pretty average number and if you start high and let gravity assist the flow of dishwasher waste you can surely push the limits a few feet... ;)

Are you planning on installing an AIR GAP or a HIGH LOOP on the dishwasher discharge? Either one should start you high enough to allow gravity to assist you.

If you don't know about the air gap or the high loop let me know and I'll explain, OK?

Mark