D-tub is an RV

Is it legal to drive around on the streets riding in a hot tub?  I went to the DMV and asked them this question, and the answer I got was "it depends on the police officer".

My plan for road driving is to have a driver in the driver's seat, and have up to three people in tub, legally calling it the "back seat" of the "RV". The back seat is the forward facing, stainless steel, and will have seat belts installed.  I plan to register the D-Tub as an RV, which I think best fits the use of the vehicle.  It also means that the  open container laws don't apply, and insurance is hopefully cheap.  It's still illegal to be drunk in the vehicle, though, unless you have a babysitter.


I can't find any list of regulations for California on what's needed to register a vehicle as an RV.  It's probably closest to a "truck camper" on the CA DMV website.  However, the Arizona motor home definition is:
20. "Motor home" means a motor vehicle that is primarily designed as temporary living quarters and that:

(a) Is built onto as an integral part of, or is permanently attached to, a motor vehicle chassis.
(b) Contains at least four of the following independent life support systems if each is permanently installed and designed to be removed only for purposes of repair or replacement:
(i) A cooking facility with an on board fuel source.
(ii) A gas or electric refrigerator.
(iii) A toilet with exterior evacuation.
(iv) A heating or air conditioning system with an on board power or fuel source separate from the vehicle engine.
(v) A potable water supply system that includes at least a sink, a faucet and a water tank with an exterior service supply connection.
(vi) A 110-125 volt electric power supply.


I've been tipped off that Progressive is the best insurance company for non-standard RVs.