Property taxes are only reassessed when there is a "change in ownership" of the property. This occurs when you sell, devise or gift a piece of property to another for inadequate consideration, meaning they didn't pay you a fair price for the property. California law is clear and says that when an individual transfers property to a revocable trust, the state does not consider this to be a "change in ownership." California Revenue and Taxation Code Section 62(d)(2).
If however you sell the property to another person, they will have to pay property taxes on the current fair market value of the property. So if you bought the house 30 years ago for $100,000, you only pay property taxes based on that amount, subject to the annual increase allowed under California law, even if you transfer the house into your revocable trust.
Gift taxes work in the same way. If you transfer the house into your revocable trust, the government will not consider this to be a transfer of the property.
A couple more notable fees include (1) recording fees which are levied by the county assessor. When executing a revocable trust, you must transfer title of the property into the name of the trust if you want the trust to work properly. A new deed must be prepared (I can do this for you) and recorded, but this only costs $15-20. (2) A documentary transfer tax is levied when selling property to another person. However, when transferring the property to a revocable trust, California law states that this transfer is exempt from the fee imposed by the documentary transfer tax because there is no consideration tendered. California Revenue and Taxation Code Section 11930. (3) Notary fee are also required when signing a revocable trust, but this fee is nominal.
I hope that gives you an idea about the costs that are associated with a revocable trust.