atwood G6A-8E water heater leaking at cold fitting

Many a leak can start from the pressure release valve too. It's only a ten dollar fix and might be worth it for an easy fix. It could leak all the way down to the inlet inside the insulation.

Is it an electric/gas model?

Put a paper towel around the fitting where you suspect it is coming from, and put the pressure to it for just a short time. You will notice the wetness on the towel before you will see the drips if it is coming from there.