why can I by these in California?
Due to the strict emissions laws in CA.
It would be very helpful if the engine MANUFACTURER was listed in the specs. Some engine brands you can get parts; others, not so much.
Check out the review on http://www.amazon.com/Steele-Products-SP-WE175-Electric-Pressure/dp/B00291X8P2 for the electric one.
Its Chinese. Good luck getting parts.
With the proper pressure-boosting upgrades, the bidet would be a cheaper option.