Sales and Property Tax
Having just been through this myself, the CA State Board of Equalization (responsible for CA sales or use tax) gets a copy of documentation activity for all of CA from the US Coast Guard. They will send you a questionaire regarding purchase price, etc. They may also check with the seller. If the seller's info and your info varies by a significant amount, an audit may be triggered. I think the SBE only gets the report from the USCG once per year so it may take them a year or so to catch up with you. Rest assured that they WILL catch up with you! They will send you a bill and give you some period of time to pay after which, some penalty will be due.As far as personal property tax, the county assessor gets reports from the marina management and, as Rick stated, from their dock walkers regarding which boats are where. If your boat is documented, they will note the name & hailing port and find out from the USCG ownership info and send you a notice of "Escaped Assessment" along with a valuation. You have 60 days to request an informal hearing if you think the valuation is too high. In my county, past year's property tax can be paid via installments but the current year's tax must be paid when due. My county's assessor was also very willing to work with me on a fair valuation, generally going with the NADA used boat values as their guide. Escaped assessments have no penalty.This is from personal experience in Alameda county just this month. I found that both the SBE and the Alameda county assessor to be very reasonable but the key is communication. For example, the county assessor lowered my boat's valuation by several thousand dollars for both years I owed property tax saving me hundreds of dollars. I had to request an informal hearing but they did lower it. If you are a legal liveaboard in CA you are also eligible for a "homeowner's exemption" which will lower the property tax valuation by $7,000 if the boat is your primary residence. Your county may be different. I would just wait and take care of sales tax & property taxes when they catch up with you. Meanwhile, budget & plan for when they do. I hope that helps. I have included a link to the CA State Board of Equalization's FAQ on use tax for boats, etc.