Is there a common leak point for the A/C in the dash area?

I noticed today that my A/C charge has been dropping. No evidence of leaks under the hood. My electronic refrigerant sniffer detected refrigerant in the vents.

Just trying to get an idea if I'll need a new evaporator or not. Thanks

93 Accord

 

Sniff the drain tube

 

I already know the leak is from inside the evaporator box.

I was just asking if the evaporator itself tends to go bad, or if its typically something else.

 

Yeah they can split a seam.