We live in California but have a rental property in Wisconsin. Do we have to file state taxes in Wisconsin for the rental incom we make on the property

Yes. You will need to report your WI-source rental income on a WI nonresident state income tax return.

You will also need to file a CA resident state tax return (for all income from all sources including WI rental income). You will get a state income tax credit in CA for any WI state income taxes that you paid on your nonresident WI state income tax return.

You will want to work on your nonresident WI state income tax return first. You will then take a tax credit from your nonresident WI state income taxes on your resident CA state income tax return. (Please note that you will only get a tax credit for your WI state income taxes up to the amount of CA state income taxes that would have been paid if the income was earned in CA).  The credit for taxes paid to another state section will be at the end of your residence state's interview process.

Just follow the TurboTax guide when working on your states (remembering to do your nonresident state return first) and TurboTax will do all the calculations and credits to your resident states return

Here is additional information about filing in multiple states (select "see more answer" to view the entire attachment)

https://ttlc.intuit.com/replies/3300797

If you have more than $2,000 GROSS income (NOT NET) in Wisconsin then you have to file.
https://www.revenue.wi.gov/pages/faqs/pcs-indreq.aspx

I paid Wisconsin tax on a rental income but my credit on California tax was not the same amount because CA tax would have been smaller for same income because it excludes social security benefits from tax while WI doesn't.