Downtown Vacancy Rates Are Crushing Commercial Property Values — What That Means for Your Tax Bill

The Vacancy Problem No One Is Talking About

Walk through downtown Des Moines on a Tuesday afternoon and count the darkened floors. Then look at your property tax assessment.

If your commercial building is assessed based on 2019 or 2020 occupancy assumptions, you are very likely overpaying — by thousands, potentially tens of thousands of dollars per year.

Why Vacancy Matters to Assessed Value

For commercial properties, county assessors are required to use an income approach to valuation. That means the assessed value should reflect what a property can realistically earn. The formula looks like this:

Net Operating Income ÷ Capitalization Rate = Value

When a third of your building sits empty, your actual net operating income drops dramatically. Yet many Polk County assessments still reflect theoretical full-occupancy income from pre-pandemic leases.

What the Des Moines Data Shows

Commercial office vacancy in the Greater Des Moines metro has climbed sharply since 2020. Key indicators include:

• Downtown Class A office vacancy: hovering near 30% in several corridors
• Suburban office vacancy: up 15–20% from pre-2020 levels in West Des Moines and Ankeny
• Average asking rents: flat or declining in real terms when adjusted for tenant improvement concessions

This is not a temporary blip. Hybrid and remote work has permanently restructured office demand across Iowa's largest market.

The Assessor's Dilemma

County assessors face a lag problem. Iowa law requires mass appraisal, meaning assessors value thousands of properties using broad data — not property-by-property income statements. When market conditions shift rapidly, the assessment rolls fall behind reality.

That gap between what your building is actually worth today and what the county says it's worth is your appeal opportunity.

How to Build the Argument

A successful commercial appeal based on vacancy and income loss requires:

1. Actual rent rolls: Document current leases, vacant suites, and any rent concessions
2. Market vacancy comparisons: Show that your vacancy is consistent with or worse than market norms
3. Reconstructed income approach: Present your actual NOI vs. the county's assumed NOI
4. Cap rate evidence: Use recent comparable sales to establish the correct capitalization rate

The Bottom Line

If your downtown or suburban office building has significant vacancy, there is a very strong argument that your assessed value is too high. The window to file appeals is limited — Iowa's typical appeal deadline falls within 30–60 days of assessment notices.

AppealIQ specializes in exactly this type of commercial appeal. We work on contingency — you pay nothing unless we win savings for you.