Building a structure would uncap taxes.
Adding utilities hook-up might not.
(There may be county restrictions on max amount/days of usage. Or they may add them in the future)
It depends on what it is planned for: Second home crash pad, relatives and friends, adding value to lot, whatever.
https://www.sccassessor.org/faq/understanding-proposition-13
"
When new construction occurs, it is re-assessed at current market value as of the date of completion. This establishes a new base year value for the property’s newly constructed improvements only"
Here, any variance to existing zoning laws requires a notice sent to neighbors to be able to voice concerns at a planning review board meeting. I've gotten them for properties blocks away for people adding on/building to the curb/ADUs/etc. Not sure how it works there or if that would be a problem.
My first though would be to contact the county directly, or an hour's consultation with a RE attorney with local experience.
Get it in writing. No point in starting something which has to be reversed.