How do you find out where your 1997 Honda Civic EX is leaking from when the passengers side floor gets wet all the time?

If the liquid is coolant, your heater core or line may have sprung a leak!

This happened to me, two huge puddles on my passenger side floor mat twice in one day. I looked up below the dash and found the hole it was dripping from. I found a nearby hose sticking out about two inches that wasn't connected to anything. Reconnected and problem solved. Just a disconnected hose.

If the hose is still connected it may just be plugged, you can free it up by probing it with a piece of wire.