Would this be considered a defect or in need of correction?
I re-read the residential plumbing overview course and it stated “dishwasher must be connected to waste line with a 32-inch minimum high drain loop or an air gap above the counter top surface”. Obviously you can see that the air gap is not above the counter top surface. The waste tee and disposal inlet are above 18" from the floor so I’m assuming that the correct way would have been to loop up and then into the disposal inlet.
Standard install. See it all the time. Only thing is the hose needs to be secured to either the cabinet or stand pipe higher up so a surge doesn’t cause the hose to come flying out, and the end of the hose should be below the opening in the Y fitting to prevent splash back.
Welcome to our forum, Dennis!..enjoy participating. 
Michael, has it the way that is acceptable around here anyway.
And nice graphic, too.
Thank you for all the responses.
Interesting. After completing thousands of inspections I have never seen it done that way.
It’s a regional thing. I never see it where I live. Some states require the anti-siphon air gap fitting installed on the countertop. Lots of different ways to attach the dishwasher to the drain system.
Same here, never have seen it.
With the disposal in place it seems like someone put in some extra effort for that type of installation.
Did they NOT know what this is for?
I too have never seen this setup before
Just a thought, the disposal may have been added after the dishwasher drain design. I too rarely see this but when I do it is in older homes.
I suspect that the OP is inspecting in a jurisdiction that follows the uniform plumbing code. UPC 807.3.
Another thought, if you hooked into the disposal, you would have to cap the standpipe, unless you wanted to hand fill the P-trap every couple of days… 
I’m curious what region you’re in/ referring to. We just bought a home (Lake Tahoe, CA) and we have this exact same setup (including the unused dishwasher to disposal connection). I’m new to home inspecting, but have spent a lot of times under sinks and I’ve never seen this either. It was interesting and I’m glad someone else had a question about it!
I believe California follows the UPC. This set up is likely very popular in the UPC territories. There are other methods that were approved by the UPC such as an airbreak device installed on the countertop.
I’m in Englewood Colorado and it’s at an apartment complex.
Go to section 802.1.8 Domestic Dishwashing Machines
You are correct Martin. The California Plumbing Code 2019 is an adopted version of the 2018 UPC.
