Dishwasher drain from early 1990's house not so great?

[MikeBell2112]

My early 1990's house in Colorado was presumably built plumbed like this. Above the Y where the dishwasher hose dumps into is an open vent pipe still inside the cabinet. (It is somewhat of an island with no wall behind the sink, so no vent to the roof and no vent pipes going out the sides.) This is on the main level with the basement underneath. I don't know how the pipes are done behind this wall.

Something clogged and the dishwasher overflowed from the Y. Water was also able to go into the sinks, but not very high since the open Y is at that level. The water in the sinks bubbled through the drain as they slowly emptied.

The clog wasn't serious, as I was able to dump bleach into the sink and it resolved. I did run the disposer before things completely drained, and that sent bleachy water shooting out of the Y and into the cabinet. That also kills my favorite unclogging technique, which is sending pressurized disposal water into the pipes.

Is this set-up even competent, should I just hook the dishwasher to the disposal, and should I cap anything to keep future drain water out of the cabinet and from then possibly dripping down into the finished basement? I am from California, so I know about an air gap installed into one of the sink holes, if that would be prudent.

 

[Reach4]

I think you should clean the drain line in the basement if you can access it. If you cannot access it, have a plumber put in a cleanout down there. I am not a plumber.

 

[Sponsor]

 

[Standardairconditioner]

You have nothing to lose by trying hand-powered snakes and augers.

If those don't work, you will need to get thru your basement pipes with a motorized auger or rodding, which is NOT recommended for a DIY and should be done by those with experience.

There are plenty of posts in the forums here that explain the DIY dangers of motor tools used to clear clogs. The reason being that these tools can be easily rented without verifying the knowledge of the renter.

 

[MikeBell2112]

It did unclog easily once the bleach had a little time to act. I'm more asking if it's a bad plumbing design and if I should change anything.

 

[Standardairconditioner]

I'm more asking if it's a bad plumbing design and if I should change anything.

The fact that you put faith in something you can pour to fix clogs reveals you lack of knowledge of how your drains work.

Nothing you change that we can see in your photo will fix your problem.

You have a clogged drain that is well below what you see in the photo.

Read what #2 said.

 

[Reach4]

Some places require a dishwasher airgap, which is usually a protrusion above the sink. That should spray water into the sink on your next blockage. The other common way is to hook the hose directly to the disposal, and loop the hose high to the underside of the counter as it passes from dishwasher to disposal. When your drain blocks up next time, the first water would go into the sink. You still should be able to clean that drain. The common place for a blockage is as the vertical transitions to horizontal.

Yes, you would cap your existing drain that the standpipe uses if you hook up to the dishwasher..

 

[Terry]

An air gap makes sure there is no siphoning back into the dishwasher. Some dishwashers have a high loop built in.
You can run the dishwasher to the disposer after the plug has been knocked out, or sometimes you see a 3/4" insert fitting for the dishwasher hose into the p-trap. I don't normally see a standpipe installed under a kitchen sink. I can see how that would be a water issue if things get slow.