A water pump can leak at a pretty good clip but not as fast as you can pour water in. It's at the front of the engine too, not the side. My best guess is you have a core plug that popped out or is corroded. Replacements are very inexpensive but you have to get the correct size for your engine, and naturally the one that leaks is always the hardest one to get to.
Before you go shopping for a new plug, remove the stuff that's in the way so you can see the leak and be sure that's what you need. The guys at the auto parts stores will be able to select the right size plug and they will likely have a drawing showing the location of all of them. If they don't, visit an engine machine shop for that information.
There are special tools for installing the new plug without deforming the soft metal, but if you're careful, you can pound them in with a large socket that just matches the outer lip diameter. Watch how far the others are pressed in so you don't go too far. The new plug starts out being a little too big so you might want to start with a little bigger socket. Once the edge of the lip is flush with the side of the block, switch to a slightly smaller socket that will just sneak inside the hole so you can keep pounding until the edge of the lip is recessed about 1/8".
I like to put a thin ring of silicone gasket sealer around the new plug but that shouldn't really be necessary. Since they are so inexpensive, you might want to buy a second plug for a spare but don't expect to have to replace all of them. It seems to be common for one to corrode through and the others look like new when they are removed.
Friday, July 15th, 2011 AT 8:10 PM