Not sure about other people's jurisdictions, but in Southern California if someone stops paying property taxes for five years, then the tax collector takes it back and sells at auction. A lot of the investors who buy these tax-defaulted parcels assume that the previous owners (aka the parties who defaulted) simply couldn't afford to pay the taxes, but actually, in some cases, the parties simply elected to abandon the property via non payment because said property has some type of challenge, i.e. zoning, access, utility/light pole dead center in front, topographic issues, soils/geotechnical issues, easements/encroachments, environmental, the list goes on. Some of those issues can be resolved if the buyer and/or a consultant they hire is savvy, but many of the buyers get frustrated and were hoping to just do a quick flip, which by the way, title companies often won't insure a tax sale property flip until a redemption period of a year or two, maybe three have passed.