1999 Chevy Tahoe coolant leak

My 99 Tahoe has had a small coolant leak for years. After the vehicle sits overnight there may be a small (3-4 inch diamater) puddle of coolant on the floor. Lately I have noticed the amount has increased. I replaced the water pump myself 3 years ago and this didn't solve the problem. It is very difficult to find the source of this leak as the coolant is blown all over the front of the engine by the fan. Is there an easy way for me to determine the source of this leak or do I need to take it in for a pressure test. I like to have a good idea of what the problem is so I can decide to either fix myself or have somebody fix. I also like to have an idea of the problem before I ask somebody to fix so I know their diagnosis is not off base.