My guess is that it is indeed leaking at the water pump. I have the same problem and I'm just going to do a waterpump and timing belt change very soon.

The only thing about removing the timing cover is that I'm sure you'll have to deal with removing the crank pulley bolt. Let us know how things go.

BTW, this is the 2nd D16Z6 I've had that has had this problem. The first snapped it's timing belt while I was on the freeway. I was ignoring the leak for a while and I'm assuming that may have contributed to the timing belt's sudden failure.