Are There Liens?

When you buy real estate, your written contract usually promises that the seller will deliver clear title.  Rather than relying on that, a prudent buyer has the public records searched, to see if there are any undisclosed liens, including those for back taxes, on the property.  Depending on local custom, the search may be done by an attorney, a title company, an abstractor or an escrow company. 
You can also look those things up yourself any time, because the public records are indeed open to anyone who cares to look.  Talk with the records office in your county.