Re: Adverse Possession in California of Bank Owned Parcel
AP was not designed for the purpose of stealing another's property. The reason it exists is partially to provide a remedy for long time good faith occupation which does not coincide with the lines of written title. Another reason was to provide a way for the occupation and productive use of properties which had been truly and completely abandoned by their title owners as happened from time to time as the West was being settled. Again, this occupation was presumed to be in good faith, that an attempt was made to locate the record owner and not surreptitiously displace them. In this case, you know who the record owner is (the bank), and you know that they have not completely abandoned their ownership of the property because they continue to pay taxes on it.
If the place is chained up and you begin to occupy it, you will be guilty of both criminal trespass and breaking and entering. If you begin paying the taxes, it will be a flag to the bank that something is amiss with that account. they will probably investigate why someone else has paid the taxes and quickly find you naively trying to take that which is not yours. At a minimum, you will be evicted. Quite possibly, you will have civil and/or criminal charges filed against you and find yourself having to pay for the legal action taken to remove you, to dispose of whatever you leave behind, and to reinstall appropriate security measures sufficient to prevent this from happening again. Plus you may come out of it with a criminal record.
If for some reason, they didn't catch the fact that someone else is paying the taxes, and decided to stop paying them just because the County is showing a zero balance each year when they check, and you get past your 5 year mark, you still would have to file your dubious claim for title by AP with the court, suing the bank for Quiet Title. If the payment of taxes don't get their attention, a lawsuit certainly will. even if you then avoided any criminal charges for B&E, trespass, and fraud, you would still have to pay several tens of thousands of dollars in legal costs to see the suit through, and then still may lose.
OK, there's the harsh reality and admonishment, now here's advice to follow if you really want the property or just want to see it cleaned up. Find out if the bank has attempted to sell it in the past. find out if they are willing to sell it now. There may be a particular reason they are holding the property, but it may only be that the cost of actively trying to sell it exceeds the cost of holding it until the real estate market improves. If a potential buyer were to approach them with a reasonable offer, which may still be below market value, it might be worth it to them to sell. If you have reasonably good credit, they might (depending upon the bank) finance it to you.
If you just want the property cleaned up, there may be avenues for that. If it is becoming a health or safety issue, the City or County Building or Health departments might be the place to go. You might first contact the bank to insist that they properly maintain the property in a safe condition. If they are already doing that, but just not painting and landscaping to the standard set by the occupied homes nearby, there probably isn't much you can do about it.
Bottom line, if you want the property, go about it honestly. If you just want the property cleaned up, first try to get the bank to do it (heck, maybe they'd hire you to do it if your qualified and give them a good proposal for it), and failing that, go to the local authorities if it poses a nuisance.
My take is that of a surveyor. One of the lawyers that frequent the forum may have better advice, but probably not much more encouraging for you.
[Edit] LS posted as I was typing. Although his post was a little more temperate than mine, our advice is closely the same. I am not necessarily anti-AP. There are circumstances when it is the best means to achieve an equitable outcome. But I am against the misuse of AP as an attempt to get something for nothing at someone else's expense. That is called 'theft'.
I'm a surveyor, not your surveyor & not an attorney.
Advice is general survey, not legal. Hire a local professional for specific advice.