Plumbing in the return air duct

What should be said about plumbing in the return air duct? House built in 2008.

Thanks! in advance for your input.

Depends on the nature of the plumbing, domestic water allowed, a indirect waste not allowed, gas lines not allowed, flue pipes not allowed. What I would say about your pic could be sumed up in one word trash. Very non-professional those pipes will allow non-conditioned air to be drawn into the return air


I agree with you, however the plumber did tape around them.