Why Your Tax Bill Just Got More Complicated
Colorado property taxes went through a significant shift after voters repealed the Gallagher Amendment in 2020. That amendment had capped residential assessment rates for decades — its repeal opened the door for rates to rise with home values, which in a market that doubled in many areas, created serious sticker shock.
The legislature responded with relief measures in 2024 and 2025, including a new "two-rate" system and a value reduction credit. The result is a tax structure that's more fair to homeowners — but considerably more complicated to calculate. Here's how it actually works.
The Two-Rate Assessment System
Beginning with the 2025–2027 tax cycle, your residential property is no longer calculated with a single assessment rate. Instead, your bill is the sum of two separate calculations — one for school districts, one for everything else:
| Portion | Assessment Rate | Covers |
|---|---|---|
| School Districts | 7.05% of actual value | Your local school district mills only |
| Local Government | 6.8% of actual value* | County, city, fire, water, special districts |
*Before applying the 6.8% rate, a value reduction credit is subtracted from the local government portion — see below.
The 2026 Value Reduction Credit
To offset rising home values, the state built in a specific credit for the local government portion of your bill. For 2026, the first 10% of the first $700,000 of your home's actual value is deducted before the 6.8% rate is applied.
On a $600,000 home, that's a $60,000 reduction — not nothing. But it only applies to the local government portion, not to the school district calculation.
The Math — Step by Step on a $600,000 Home
You need two separate calculations, then apply your local mill levy to the combined assessed value:
| Step | Calculation | Result |
|---|---|---|
| School assessed value | $600,000 × 7.05% | $42,300 |
| Value reduction credit | $600,000 × 10% | −$60,000 |
| Local gov assessed value | $540,000 × 6.8% | $36,720 |
| Total assessed value | $42,300 + $36,720 | $79,020 |
Your final tax bill is then: Total Assessed Value × Total Mill Levy ÷ 1,000. A mill represents $1.00 of tax per $1,000 of assessed value. At a combined 80-mill levy, that $600,000 home owes roughly $6,322 per year — about $527/month.
County Comparison: What NoCo Homeowners Actually Pay
The three-county NoCo region is remarkably close in effective tax rates, but the absolute dollar amounts vary with median home values:
| County | Median Home Value | Median Annual Tax | Effective Rate |
|---|---|---|---|
| Boulder | $783,000 | $4,283 | 0.55% |
| Larimer | $610,000 | $3,146 | 0.52% |
| Weld | $496,100 | $2,688 | 0.54% |
The county-level differences are real but not dramatic. The far bigger variable is whether a specific property sits in a metropolitan district — that alone can add more to your bill than the entire county rate difference. See our Metro Districts guide before assuming the county rate tells the whole story.
The Variable Nobody Shows You: Metropolitan Districts
If you're buying in a newer development in Timnath, Windsor, Johnstown, or parts of Loveland and Fort Collins, you are almost certainly within a Metropolitan District. These quasi-governmental entities were created by developers to finance infrastructure — roads, water, sewer — and homeowners repay that debt through an additional mill levy on top of everything else.
Think of it as a second mortgage baked into your property tax bill — one that doesn't appear in the MLS listing, isn't reflected in the county's estimated tax rate, and cannot be appealed or negotiated away.
| District Type | Typical Mill Levy | Annual Cost on $600K Home |
|---|---|---|
| Standard / Established | 65–85 mills | ~$3,146/yr (base taxes only) |
| New Development District | 120–155+ mills | $6,200+/yr |
Note: Metro district mill levies are set by the district's board. You cannot protest them through the County Assessor — only the assessed market value of your property is protestable.
Always ask for the full mill levy breakdown before making an offer — not just the county's estimated tax rate. The subdivision's Mill Levy Disclosure is the document you need. I pull this for every buyer I work with.
The Market Lag Defense: When to Protest
Colorado assessments are based on a specific snapshot in time: sales data through June 30, 2024. If the market in your neighborhood has softened since then — or if your home has condition issues not reflected in comparable sales — your current assessed value may be higher than what your home would actually sell for today.
That gap is your protest argument. Gather closed sales of similar homes in your area from late 2024 or early 2025 that closed at or below your assessed value. Present them during the May 1–June 8, 2026 protest window. The Assessor is legally required to review and respond.
If the Assessor denies your protest, you can escalate to the Board of Assessment Appeals. It takes time, but a successful protest locks in a lower assessed value for the entire 2025–2027 tax cycle — worth doing if the number is meaningfully off.
Senior Property Tax Exemption
Colorado offers a meaningful exemption for qualifying senior homeowners: 50% of the first $200,000 of your home's actual value is exempt from property tax. That's up to $100,000 off the top before the assessment rate is even applied.
To qualify, you must: (1) be 65 or older as of January 1 of the tax year, and (2) have owned and occupied the home as your primary residence for at least 10 consecutive years. Apply through your County Assessor's office — it's not automatic.
2026 Deadlines Every NoCo Homeowner Should Know
For your 2025 taxes payable in 2026, Larimer and Weld County Treasurers operate on this schedule:
| Deadline | What It Is |
|---|---|
| February 28, 2026 | First half installment due (if paying in two installments) |
| April 30, 2026 | Full payment due (if not using the installment plan) |
| May 1 – June 8, 2026 | Window to formally protest your assessed value with the County Assessor |
| June 15, 2026 | Second half installment due |
Assessor websites: Larimer County at larimer.gov/assessor, Weld County at weldgov.com/assessor. Both allow you to look up your current assessed value, tax bill breakdown, and mill levy detail for any parcel.
Frequently Asked Questions
Why did my Colorado property tax bill change so much recently?
Two things happened. First, the Gallagher Amendment — which had capped residential assessment rates for decades — was repealed in 2020, allowing rates to rise with home values. Second, Colorado's legislature responded with new relief measures in 2024–2025, including the two-rate system and the value reduction credit, to offset the impact of rapidly rising home values on tax bills.
Why did my tax bill go up if the legislature 'lowered' the rates?
Because rate and bill are not the same thing. Even if the assessment rate dropped slightly, a 25–30% jump in your home's assessed value produces a higher bill. Example: a 7% rate on a $700,000 home ($49,000 assessed) yields a larger bill than a 7.5% rate on a $500,000 home ($37,500 assessed). The legislature lowered the rate to partially offset rising values — but if values rose faster than the rate fell, your bill still went up. This is sometimes called tax compression.
What is the two-rate property tax system in Colorado?
Starting with the 2025–2027 tax cycle, Colorado assesses residential property at two different rates depending on the taxing authority. The school district portion is assessed at 7.05% of actual value. All other local government entities (county, city, fire, water districts) are assessed at 6.8% of actual value, with an additional value reduction credit applied. You add both calculations together to get your total assessed value.
What is the 2026 value reduction credit?
For the local government (non-school) portion of your tax bill, Colorado deducts 10% of the first $700,000 of your home's actual value before applying the 6.8% assessment rate. On a $600,000 home, that's a $60,000 reduction — lowering your local government assessed value from $40,800 to $36,720. It's a meaningful reduction, but it doesn't apply to the school district portion.
Which Northern Colorado county has the lowest property taxes?
Based on 2026 median effective rates, all three NoCo counties are close: Boulder at 0.55%, Weld at 0.54%, and Larimer at 0.52%. Larimer edges slightly lower on the effective rate, but Weld County's lower median home values mean lower absolute dollar amounts. The bigger variable for any specific property is whether it sits in a metropolitan district — that can add more to your bill than county differences ever would.
When are property taxes due in Larimer and Weld counties in 2026?
For 2025 taxes payable in 2026: First half installment is due February 28, 2026. Full payment (if not using installments) is due April 30, 2026. Second half installment is due June 15, 2026. The window to protest your assessed value with the County Assessor runs May 1 through June 8, 2026.
How do I protest my property's assessed value in Colorado?
Between May 1 and June 8, 2026, you can file a formal protest with your County Assessor if you believe your property's market value is lower than the assessed value. Colorado assessments are based on sales data through June 30, 2024 — so if the market softened after that date, your current market value may be lower than the assessed value. Bring comparable sales from 2024–2025 that closed near or below your assessed value. The Assessor reviews and responds; if you disagree with their decision, you can appeal further to the Board of Assessment Appeals.
Does a metropolitan district affect my property tax calculation?
Yes, significantly. Metro district mills are added on top of all county, city, and school district mills. Standard established districts run 65–85 mills; newer development districts routinely run 120–155+ mills. On a $600,000 home, that difference is roughly $3,146/year vs. $6,200+/year — before even counting county and school taxes. Importantly, you cannot protest metro district mills. You can only protest the assessed market value of your property. The metro district mill levy is set by the district's board and is not subject to the County Assessor protest process.
How do I find out the total mill levy for a specific property?
The most reliable method is to look up the property's actual tax bill through your county assessor's website — Larimer County at larimer.gov/assessor, Weld County at weldgov.com/assessor. The tax bill breaks out every taxing authority and its mill levy. Your real estate agent can also pull this for any property you're considering before you make an offer.
Is there any property tax relief for seniors in Colorado?
Yes. Colorado's Senior Property Tax Exemption exempts 50% of the first $200,000 of a qualifying home's actual value from property tax. To qualify: you must be 65 or older as of January 1 of the tax year, and you must have owned and occupied the home as your primary residence for at least 10 consecutive years. The exemption is applied before the assessment rate calculation, so the savings are real. Apply through your County Assessor's office.