What if I pay half of the property taxes on a home?

Do you own or co-own the property?  Is your name on the mortgage or the deed?

Please see this TurboTax FAQ for more information about paying property (real estate) taxes: 

https://ttlc.intuit.com/replies/3300663

Do I need to pay half of my 2019 WI property tax to get a WI income tax credit?

I don't see anything under the Wisconsin Property Tax Relief Credits saying that you have to pay any specific percentage of your property tax to get a credit. It appears that you may be entitled to a Homestead credit based on your income and other eligibility requirements.

There's no mention of what state you are in. But on the federal side there are two basic criteria that must be met in order for you to claim property taxes paid.

 1) You must be legally obligated to pay them.

 2) You must actually have paid them.