Dishwasher drain installation

Drain hose installed into kitchen sink drain line in the crawlspace. The T- fitting is where diswasher ties in, just after/below sink drain. Comments?What would be the proper way to do this if not tying in directly under the sink?

Y connection.
make sure there is an air gap or high loop for the DW drain also.

What’s up with that trap down there?

Check with the installation manual if possible but the installation manuals that I’ve seen are written that the drain hose has to be terminated no lower than 18 to 20 inches from the floor where the dishwasher is installed.

Such as what’s written on page 7 here.

So in other words, correction is needed as noted per manufacturer.

Don’t forget to write up that the trap is also improperly installed if it’s not already double trapped. The pipe from the sink to the trap is installed lower than on the other side of the trap. That means the pipe where the dishwasher is draining into is always holding water.

Overall it’s just wrong and correction should be made to ensure proper performance.

You probably already noted that but just in case.

This must be what you meant on page 7

No waste disposer – with air gap:

  1. Cut end of drain hose if needed (do not cut ribbed
    section).
  2. Attach drain hose to air gap with large spring-type
    clamp. If the drain hose was cut, use a 1-1/2" to 2"
    (3.8 to 5 cm) screw-type clamp*.
  3. Use a rubber hose connector* with spring or screwtype
    clamps* to connect air gap to waste tee.
    This connection must be before the drain trap and at
    least 20" (50.8 cm) above the floor where dishwasher
    will be installed.

That is just referring to the air gap.

Your right Kevin, just installed new dishwasher in my own home and the instructions said at least 18 inche above the floor, or here in Canada 45 cm. or more eh.

I used to install them for a living and it is ok as long as you have a reverse loop.

So the T-fitting not being a drainage type fitting and the kitchen sink being “double trapped” is the issues at hand, correct? Again I ponder, what would be the proper way to tie in the dishwasher drain to an existing drain line, when installed underneath in the crawlspace, as in this case? If this install didn’t have the inline trap and it was tied in with a drainage T or Wye, would this be o.k?

Here’s a pic of the DW drain:

No. If the trap was installed in the proper location the dishwasher drain would be tied in downstream of the trap. The DW drain should tie in on the sanitary side of the trap. The existing trap location is wrong whether there is one trap or two. Both the sink and the DW drains are improper and you can’t fix one without the other.