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Updated 2025 Tax Year

Costilla County
Property Tax Guide

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

10 Official Sources
8 min read
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Quick Facts
Tax Rate
Varies by location due to special districts, typically ranges from 15-25 mills
Exemptions
4+ Available
Section 1

How Property Tax Works

Costilla County, Colorado operates under the state's property tax system to fund essential local services including schools, law enforcement, fire protection, roads, and county operations. Property taxes are levied based on assessed value, which is calculated using Colorado's assessment rate system. For the 2025 tax year, residential properties are assessed at 6.4% of their actual (market) value, representing a reduction from previous years as part of statewide property tax relief efforts.

The effective tax rate in Costilla County varies significantly by location within the county due to different combinations of special taxing districts, including school districts, fire protection districts, water districts, and other local governmental entities. Property owners should expect their actual tax rate to differ based on their specific address and the overlay of taxing jurisdictions that serve their property. The county uses a two-installment payment system, with taxes typically due by February 28th for the first half and June 15th for the second half, though full payment by April 30th avoids any penalties.

Section 2

What Makes Up Your Tax Bill

ComponentRate (mills)Description
County GeneralVaries by districtBasic county services and operations
School DistrictVaries by districtLocal school funding and operations
Fire ProtectionVaries by districtFire and emergency services
Library DistrictVaries by districtPublic library services
Water/SanitationVaries by districtWater and sewer services
Special AssessmentsVaries by districtVoter-approved bonds and improvements

Note: These rates apply to the 2025 levy year. The residential assessment rate is 6.4% of actual value for non-school district levies. Actual mill levies vary significantly by location within Costilla County depending on which special taxing districts serve each property. Contact the Costilla County Assessor's Office for specific rates applicable to your property address.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Costilla 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 taxes in Costilla County are triggered by changes in property ownership, new construction, or improvements that increase a property's assessed value during the tax year. When these events occur after the assessment date (typically January 1st), a supplemental tax bill is issued to account for the change in assessed value for the remaining portion of the tax year.

For example, if a homeowner completes a $50,000 addition to their home in June, the supplemental tax would be calculated on the increased assessed value (at 6.4% of $50,000 = $3,200 additional assessed value) multiplied by the applicable mill levy rate, then prorated for the remaining months of the tax year. The supplemental bill would cover approximately 7 months of additional taxes on the improvement, ensuring the county receives appropriate tax revenue for the enhanced property value during that fiscal year.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value (6.4%): $19,200
  • Estimated Mill Levy: 35.0 mills
  • Annual Tax: $672
  • Monthly (if escrowed): $56

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value (6.4%): $38,400
  • Less: Senior Homestead Exemption (if qualified): $6,400
  • Net Taxable Value: $32,000
  • Estimated Mill Levy: 40.0 mills
  • Annual Tax: $1,280
  • Monthly (if escrowed): $107

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value (6.4%): $64,000
  • Less: Senior Homestead Exemption (if qualified): $6,400
  • Net Taxable Value: $57,600
  • Estimated Mill Levy: 42.0 mills
  • Annual Tax: $2,419
  • Monthly (if escrowed): $202

Note: These calculations use estimated mill levies and actual rates vary by specific location within the county. Tax credits require application and are not automatically applied.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Costilla County require property tax escrow accounts, where monthly tax payments are collected along with principal and interest payments. Lenders typically collect 1/12th of the estimated annual property tax each month, holding these funds in escrow until tax payments are due. The escrow account is analyzed annually, and any shortage or surplus results in an adjustment to monthly payments.

Property owners with escrow accounts should verify that their lender receives and pays tax bills on time, as late payment penalties will still apply even if the delay is due to lender error. Tax bills are typically mailed in December for the following year's taxes. Homeowners can verify payments and check balances through the Costilla County Treasurer's office. Those without escrow accounts are responsible for making payments directly to the county by the February 28th and June 15th due dates, or in full by April 30th to avoid penalties.

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Section 6

Frequently Asked Questions

Q: When are property taxes due in Costilla County for the current fiscal year? A: Property taxes are due in two installments: first half by February 28th and second half by June 15th. Alternatively, you can pay the full amount by April 30th without penalty.

Q: What tax credits are available and do I need to apply? A: The primary tax credit is the Senior Homestead Exemption, which provides an exemption on 50% of the first $200,000 of actual value for qualifying senior citizens. This credit requires application and is not automatic - you must apply through the Costilla County Assessor's office.

Q: How does the Homestead Exemption work? A: The Senior Homestead Exemption reduces the actual value subject to taxation, not the market value. It applies to 50% of the first $200,000 of actual value for qualifying seniors and surviving spouses. You must file an application to receive this benefit.

Q: How often are properties reassessed? A: Colorado law requires properties to be reassessed every two years. The county assessor reviews market data and adjusts actual values accordingly, though assessment increases may be limited by various factors.

Q: What are the penalties for late payment? A: Late payments incur penalties and interest charges. The first half payment is subject to penalty if not paid by February 28th, and the second half if not paid by June 15th.

Q: Can I pay my property taxes online? A: Contact the Costilla County Treasurer's office to inquire about online payment options and accepted payment methods for property taxes.

Q: How do special district taxes affect my bill? A: Special districts for fire protection, schools, libraries, and other services each levy their own mill rates. Your total tax bill includes all applicable district levies based on your property's location.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the Costilla County Board of Equalization during the protest period, typically in May and June. Contact the Assessor's office for specific deadlines and procedures.

Verified Sources

Backed by 10 Official Government Sources

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

01
2025 Property Assessment Study ...costillacounty.gov
02
Tax Doc
Understanding Property Taxes in Coloradodpt.colorado.gov
03
County
Helpful Information | Costilla County COcostillacounty.gov
04
Tax Doc
2022 ABSTRACT OF ASSESSMENT AND TAX LEVIEScostillacounty.gov
05
Colorado Senior Propertyspl.cde.state.co.us
06
Tax Doc
Senior Property Tax Homestead Exemption Short Formcostillacounty.gov
07
Tax Doc
Senior Property Tax Homestead Exemptioncostillacounty.gov
08
Tax Doc
property tax exemption for gold star spouses overviewcostillacounty.gov
09
Appendix A 2023-24leg.colorado.gov
10
HB 24B-1001 - Final Fiscal Notecontent.leg.colorado.gov
All sources verified as of 2025 Tax Year

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