property has lava-rock in excess. How does one put in fence posts?

[calsr1991]

I posted this in another past thread:

"If you have solid rock at the surface, that's the best situation. Rent a hammer drill and a 1 1/2" bit, drill a hole about 12" deep, hammer in T-post. Repeat."

1 3/8" is the better size but 1 1/2" works too.

As for the septic system a contractor is required for it to be legal.  They will have their own equipment.  Mine used an excavator with jackhammer and bucket attachments, switching back and forth as needed.

Can they install the septic system with no house plan or permit? Or is the house permit required?