Property management called about a gas leak in the csst piping. there was no bonding and lighting punctuured a hole in the pipe. Now they want it bonded. It is a pool house feeding a boiler for the pool heater. Does my #6 need to go back to the service in the main building or can I take it to the 200amp sub in the basement? I don't know if the sub panel has a ground rod. Thanks.

Corrugated Stainless Steel Tubing ( CSST ) plainly functions like a CHOKE during lightning events.

Hence, one should give it the full GEC bonding treatment...

With bushings at every choke point.

Corona discharge is prone to punch through at sharp turns - right through the PVC skin. So, every attempt should be made to not have them.

I'd take my bonding run as far back as necessary to assure that I've got an equipotential plane.

Here in NJ you have to take a ground clamp on the customer side of the gas pipe back to the grounding electrode of the electrical service. That means to me, you can connect to the #4 cu wire at the ground rod, or hit the inter-system grounding point of the electrical service. I believe there are a few more options, but these are the easiest to follow.