Can the city water utility put a lien on a property after I purchase the property?

I put an offer on a house and now am finding all kinds of horrid things about the previous owners (they were robbers and are in jail now) and how buying a foreclosure may be a mistake. I called the city water utility and they said the previous owners owed $750 in water bills and the city water utility will file a lien against the property. I am asking the mortgage company (sellers) to take care of this, but I don't know if they will. Is it legal for the water utility to put a lien on the property in Texas? Also, what other liens could I expect to pop up after I buy the house if I buy it? For example, could credit card companies, child support, federal tax liens be filed after the property is sold? The type of deed the seller is offering is a limited warranty deed that doesn't seem to offer full protection. I am getting title insurance, but after reading the title insurance policy, it seems they don't protect you from loss against any lien or title asserted that is filed on the house after I purchase it. The title company is only responsible for liens and claims on the property that were recorded before the purchase., more