Lavatory latch

There are a couple possibilities. You could have an internal latch like our 10-563 along with the 10-557 ADA handle. Take note that, when replacing that internal latch, check to see if your door has welded corners. If it does, you will not be able to access the 10-563. For doors that are screwed or snapped together, you might be able to take the door apart to get to the internal latch.

You could also try to install a surface mounted type latch like the 10-401 for inswing or the 10-402 for outswing doors.