water leak

I have water leaking from what appears to be the heater core. I did a search and think it is a clogged drain tube coming from the housing from the evaporator. How do I go about cleaning that out?

Are you running a/c? If so then you could have a clogged condensate drain dumping onto your floor. If you aren't running a/c then you likely have a leaking heater core that will need replaced. I've heard of folks using compressed air to unclog drain tubes and others who have used a piece of brazing rod coming up from underneath. So far I haven't had to do this job myself, yet.....