Putting up a shop in CA - fire department being a pain

Not trying to be a jerk here, but have you asked them if they have 150' of hose on their 70,000 lb. trucks...
I have never heard of such nonsense, and I deal with the local fire dept. regularly and have done so for years. How do they respond to farm or brush fires?
Oh, I see you're in CA... do they want you to install charging stations for the electric firetrucks they're going to be required to get, also?
I feel sorry for you. Speak with your local building inspector or local councilman/woman.

The area of dirt in the back would get them to within 100' of the shop. They said they have to be within 150' so you're right about the 150' hose.

I expected the county to require all sorts of CA bullshit but not the fire department. Your question about farm and brush fires is a good one.