Help with Milwaukee Property Tax

[Brie Schmidt]

I am hoping someone from the Milwaukee area can help me with some questions on property tax. I am under contract for the below property

http://assessments.milwaukee.gov/remast.asp?taxkey

When I go to Tax Balance

http://itmdapps.milwaukee.gov/taxAccountBalance/TaxBalServlet?itaxkey=&ichkdgt=6&isubacct=0&ismonth=052014

It says the total tax is $5981 but then in the summary section it says the total is $3515 and it has a special tax of over $4k which the seller says is because of adding a water meter and it wont continue past this year - any way to verify that?

Are taxes in arrears? How are payments made? Biannual? Quartlerly?