I have a basement floor drain that the washing machine currently connects to. Right now it's connected in unprofessional way involving a length of guttering and basically duct tape.

I examined the drain and it does seem to have a p-trap installed and it is vented, however I don't see any threads or any obvious way to connect a pipe to it. It seems to be cast iron and it's installed under the slab concrete floor.

Siberia...

Actually, you would not usually make a DIRECT connection to the floor drain... ;) Here, you would run pipe to drain but leave so pipe is about 1.5" above the drain... as long as area around floor drain is pitched. This is an example of an indirect waste line.

Here, if within say 5-10 feet from washer to floor drain then you may just be able to run drain from washer directly to the drain (but connects indirectly).. almost as you have it now... but change over to 2" PVC pipe and connect so a 90 degree elbow ends up about 1.5" above drain.

If over say 10 feet from washer to floor drain then you may need to add a p-trap and a vent (or mechanical vent)...even though connecting to properly vented floor drain... depends on plumbing codes in your area.

If area around floor drain isn't pitched...let us know!

Let me know more here...

MARK