The said books, maps and plans shall be carefully preserved in the office of the bureau, and shall be so kept, by additions from time to time, or otherwise, as to show the ownership of every lot or piece of real estate or subdivision thereof within the county limits, with the succeeding transmissions of title from the date of the commencement of such plans; but nothing therein, or in this act, shall invalidate any county or municipal or tax claim, by reason of the fact that the same is not assessed or levied against the registered owner.
16 P.S. § 9903