i have a 2000 ford taurus....i just CHANGED THE WATER PUMP, NOW ITS LEAKING FROM THE MIDDLE WHERE THE ENGINE IS....REALLY FAST....WHAT COULD IT BE???

Gasket may have moved out of position. Hose loose or bad water pump if it out the pulley shaft.

Without scaring the surfaces the gasket material all has to be removed and cleaned with either gasket surface cleaner or other methods and I apply a little old style copper gasket maker (sometimes hard to find) to hold the new gasket in place(let cure for a few minutes until it will not fall off) The old style ask for it any auto store manager will know what the old style copper gasket maker is and if need be it can be used on its own without the paper gasket, and you can apply it (thin layer) to one surface let air for a few minutes until tacky then stick the gasket to that surface and then put thin layer to other surface mounting, let air a few minutes and install it tighten down evenly or do as above and do not use the paper gasket just let it air for about 5-10 minutes (until Tacky, can touch it without it sticking to you) then install.