2015 Gateway 3650 BH Rear grey tank

HI there,
I noticed the other day the rear grey tank was leaking right at the exit pipe that leads to the flushing valve, where there is a fair amount of foam sealant. Upon further investigation I realized that the tank is actually covered by a black plastic cover, which I also realized that the leak was coming from that cover being full of water and over flowing. I drilled a tiny hole at the lowest point of the cover to drain all the water out, nothing leaking since.
I am guessing I have overflowed the grey tank and the excess water dripped into the black cover but just wanted to know how would the grey tank overflow in there, thought if the tank is full it would back up to the sinks.

Hope this all makes sense, thank you for your help.

Fred

I believe you are correct on the grey tank overflow. Depending on the amount of overflow, you may want to consider dropping the chloroplast (black plastic on underbelly) to let things dry out good.

There is a very good chance the water could be coming from you camp kitchen line if you use it a lot. There is a flexible line above that gray tank and can crack over time that comes from the camp kitchen. That lower pan can also collect rain water just from driving as well