Gas and Oil Home Heating Furnaces - Water running off A/C unit

My rooftop A/C and Heating unit is leaking water. I noticed the water running down the roof a month ago, but it was a trickle and I thought it was normal. Yesterday I noticed it has increased to 3 small streams of water that run down the roof whenever I use the A/C. I've turned the unit off (and it's hot where I live) until I can find out whether this is normal or not. Are A/C units supposed to do this? If not, what might be causing it?

That would be the condensate. Humidity that is removed from the air inside your home is condensed into water when it passes over the cooling coil. It runs out a drain and in your case onto the roof. Nothing to be concerned about. Turn it back on.

Thank you for your speedy reply! I would never have guessed this is normal, especially since it is suddenly so much water (literally, running off to the degree that it is splashing and coursing through my gutters) so you were a big help. Any idea why there would be such an increase in the amount of water now as opposed to a month ago?

Its all to do with how the humidity is now where you live. Also what you do in the home .Like more baths more washing in the home all of this will make more moisture that the AC unit has to take out.Make sure your air filters are clean all the time.;) ED

I think both of you hit the nail right on the head. I have been cleaning a lot more and I also haven't changed the filter in a very long time. I'll change it now, and try to use less water when I clean! Doityourself.com saves me once again. :D