I cant seem to find water leak on back block on 1997 Cadillac Catera

I traced the hoses into the block and it seems like it comes out as fast as you pour it on driver side

Asked by for the 1997 Cadillac Catera
In my case it could be two things the cooling tube running on the passenger side of the engine to the back of the block there is an O-ring that may need to be replaced or the heater control valve may be leaking that is located back of engine towards the top that was my issue slowly started leaking and 2/3 years turned into a major leak