In California, the tax assessors office does not do tax lien auctions. If a homeowner is in default on their taxes (I think its after 5 years!), they can sell the home at court auction, but it is for fair market value - not just the amount of the taxes owed as in some other states.
You can contact the local county tax assessors office for more information on this subect.
The best way is to contact the county Assessor Office. Ask for the schedule of auctions. In California, the owner must be in tax deault for 5 years in order to be on tax lien balck list. DO your homework before purchase any property to see what besides the tax lien to avoid unexpected surprise pitfalls later. Good luck.
Ask them for a list of "Lis Pendens". Not sure if that's what you're looking for, but I hope it gets you started.