HonestCasa logoHonestCasa
All Tax Guides
Updated 2025 Tax Year

Sioux County
Property Tax Guide

Everything you need to know about property taxes in Sioux County, IA. Rates, due dates, exemptions, and how it affects your monthly payment.

10 Official Sources
8 min read
Calculate Your True CostMortgage Calculator
Quick Facts
Tax Rate
Approximately 1% average, varies by taxing district and location within county
Exemptions
5+ Available
Section 1

How Property Tax Works

Property taxes in Sioux County, Iowa serve as the primary funding source for essential local services including public schools, county government operations, emergency services, and infrastructure maintenance. The county follows Iowa's state property tax system, where properties are assessed at market value and taxed according to rates set by various local taxing authorities including the county, cities, school districts, and special service districts.

Effective property tax rates in Sioux County typically range around Iowa's statewide average of approximately 1%, though actual rates vary significantly by location within the county due to different combinations of special taxing districts. Rural properties may have different rate structures than those within city limits, and areas served by different school districts will see varying rates. Property owners should note that most tax credits and exemptions require annual application and are not automatically applied to tax bills.

The county operates on a fiscal year basis, with assessments reflecting market values as of January 1st each year. Tax rates are finalized annually by the various levy authorities, and the total tax burden depends on which taxing districts serve your specific property location.

Section 2

What Makes Up Your Tax Bill

FY 2025-2026 Tax Levy Components (Rates subject to final approval by levy authorities)

ComponentEstimated Rate RangeDescription
County General Fund$3-5 per $1,000Basic county services, roads, law enforcement
School District$12-18 per $1,000Varies by district - Orange City, MOC-Floyd Valley, etc.
City/Municipal$8-15 per $1,000City services (applies only within city limits)
Agricultural Extension$0.50-1.00 per $1,000County extension services
Emergency Services$1-3 per $1,000Fire, ambulance, emergency management
Community College$1-2 per $1,000Northwest Iowa Community College

Note: Final rates for FY 2025-2026 have not been finalized. Actual rates vary by specific location within Sioux County based on which taxing districts serve your property. Rural properties typically have lower total rates than properties within city limits. Contact the Sioux County Assessor's office for location-specific rate information.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Sioux County, property taxes are due in two installments:

Pro tip: If you pay through mortgage escrow, your lender splits these payments across your monthly mortgage. If you pay directly, set calendar reminders to avoid late penalties.
Section 4

Supplemental Tax Bills

Supplemental property taxes in Sioux County are additional tax assessments that occur when there are mid-year changes to a property's taxable value. The most common triggers include new construction completion, major improvements or additions, changes in property ownership that remove existing exemptions, or corrections to assessment errors discovered after the regular tax roll is finalized.

When a supplemental assessment occurs, the additional tax is calculated by applying the current year's tax rate to the increased assessed value, prorated for the portion of the tax year remaining. For example, if a $100,000 addition to your home is completed and assessed in January, you would owe the full year's additional tax on that improvement. However, if the same addition is completed in July, you would owe approximately half the annual additional tax.

Supplemental tax bills are typically issued within 30-60 days of the triggering event and become due immediately upon issuance. Unlike regular property tax bills that follow the September/March payment schedule, supplemental taxes must be paid within 30 days to avoid penalties and interest charges.

Example Calculation

Example 1: $300,000 Home (with Homestead Credit)

  • Market Value: $300,000
  • Homestead Credit Applied: Limits assessment increase
  • Estimated Annual Tax: $2,400-3,600
  • Monthly Escrow: $200-300

Example 2: $600,000 Home (with Homestead Credit)

  • Market Value: $600,000
  • Homestead Credit Applied: Limits assessment increase
  • Estimated Annual Tax: $4,800-7,200
  • Monthly Escrow: $400-600

Example 3: $1,000,000 Home (with applicable credits)

  • Market Value: $1,000,000
  • Available Credits Applied: Varies by qualification
  • Estimated Annual Tax: $8,000-12,000
  • Monthly Escrow: $667-1,000

Important Notes: These examples assume application for available tax credits. The Homestead Credit must be applied for annually and caps assessment increases rather than reducing market value. Military Veterans' Exemption and other credits require separate applications. Actual taxes vary significantly based on specific location within Sioux County and applicable taxing districts.

See How Taxes Affect Your Payment

Property taxes are just part of your total monthly cost. Get the full picture.

Calculate Now
Section 5

Escrow & Property Taxes

Most mortgage lenders in Sioux County require property tax escrow accounts to ensure timely payment of property taxes. Your lender collects monthly escrow payments along with your mortgage payment, typically 1/12th of your annual property tax bill plus a small cushion for potential increases.

Property taxes in Sioux County are due in two installments: September (for the first half) and March (for the second half). Lenders typically pay the September installment on time, but property owners should verify payments are made correctly. The county mails tax statements in August, and you should review these even if your lender handles payments to ensure accuracy.

Escrow accounts are analyzed annually, and lenders will adjust your monthly payment based on actual tax bills and account balances. If property taxes increase due to reassessment or rate changes, expect your monthly escrow payment to increase accordingly. You have the right to request escrow account statements and can challenge incorrect calculations or payment errors.

How HonestCasa Helps
  • Understand whether your escrow is set correctly
  • See how rising taxes will change your monthly payment
  • Plan ahead instead of being surprised by "shortage" letters
Section 6

Frequently Asked Questions

Q: When are property taxes due in Sioux County for FY 2025-2026? A: Property taxes are due in two installments - September 30, 2025 and March 31, 2026. If unpaid by April 1, properties are listed for tax sale, scheduled for June 16, 2026.

Q: What tax credits are available and do they require application? A: Main credits include the Homestead Credit (caps assessment increases, requires annual application) and Military Veterans' Exemption (for qualified veterans, requires application). Most credits are NOT automatic and must be applied for annually through the County Assessor's office.

Q: How does the Homestead Credit work? A: The Homestead Credit doesn't reduce your home's market value but limits how much your assessment can increase year-over-year. You must apply annually, and it only applies to your primary residence.

Q: When can I appeal my property assessment? A: Assessment protests must be filed April 2-30 annually. The Board of Review meets in May to hear appeals. The assessment date is January 1st each year.

Q: What are the penalties for late property tax payments? A: Late payments incur interest and penalties. After April 1st, unpaid taxes result in the property being offered for tax sale in June.

Q: Can I pay property taxes online? A: Contact the Sioux County Treasurer's office for current online payment options and accepted payment methods.

Q: Why do tax rates vary within Sioux County? A: Different combinations of school districts, cities, and special service districts create varying total tax rates. Rural properties typically have lower rates than properties within city limits.

Q: How often are properties reassessed? A: Iowa requires assessment of all properties annually as of January 1st, with values reflecting market conditions as of that date.

Verified Sources

Backed by 10 Official Government Sources

Every fact in this guide is sourced from official county, state, and federal documents.

01
County
2024 - 84 - Sioux County - Taxable Valuations By Levy ...siouxcountyia.gov
02
Local Government Property Valuation Systemsiouxcountyia.gov
03
County
Taxable Valuations By Levy Authority & Countysiouxcountyia.gov
04
County
Sioux County Assessorsiouxcountyia.gov
05
Tax Doc
Notice to Tax Sale Purchasers 2025siouxcountyia.gov
06
Tax Doc
How Do I Pay Property Taxes?iowa.gov
07
NXT 4 PRINTsiouxcountyia.gov
08
File a Homestead Exemptioniowa.gov
09
County
MINUTES OF SIOUX COUNTY BOARD OF SUPERVISORSsiouxcountyia.gov
10
Tax Doc
Property Tax Reformlegis.iowa.gov
All sources verified as of 2025 Tax Year

See the Full Picture of Your Home Costs

Property taxes are just one piece of homeownership. HonestCasa helps you understand your total monthly cost and explore safe ways to access your home equity.

Total Monthly Cost

Mortgage + taxes + insurance + HOA

Equity Growth

Track how your equity grows over time

Safe Equity Access

Options for projects or debt payoff

Run Your ScenarioTry Calculator

Free • No credit check • 2-minute estimate