Whenever I purchase a property at trustee sale in Maricopa county I always check the county assessor website here http://mcassessor.maricopa.gov/assessor// . Once on the website you type in the parcel number for the property on the right hand side and click go. Then towards the top of the page where it says 'Owner Information look' for 'view tax information' and click on it. You can then view what has been paid for each tax year. If it says $0 then you know the taxes have not been paid for that year. Buying at trustee sales can be a little complicated so if you don't know what you are doing you may want to hire a bidding service to help you.