What Does Amendment 87 Mean for Douglas County? The Graduated Income Tax, by Household Income

Amendment 87 is the biggest tax question on any Colorado ballot in a generation, and no county has more skin in it than this one. Douglas County has the highest median household income in the state and, by any measure, one of the largest concentrations of households above $500,000. Amendment 87 cuts taxes slightly for the first group and raises them substantially for the second. Here is what that means at your kitchen table.

The math, household by household

The brackets apply to Colorado taxable income, which for most families is federal taxable income: gross income minus the standard deduction (about $30,000 for a married couple) or itemized deductions. So a household grossing $150,000 is roughly $120,000 taxable. Our examples below are taxable income, and the change is against today's flat 4.4 percent.

• $75,000 taxable: $3,300 today; $3,025 under 87. Saves $275.
• $100,000: $4,400 today; $4,075. Saves $325.
• $150,000 (roughly the Douglas County median household, $145,700 gross): $6,600 today; $6,275. Saves $325.
• $250,000: $11,000 today; $10,675. Saves $325.
• $500,000: $22,000 today; $21,675. Saves $325. This is the top of the cut.
• $600,000: $26,400 today; $29,075. Pays $2,675 more.
• $750,000: $33,000 today; $40,175. Pays $7,175 more.
• $1 million: $44,000 today; $59,925. Pays $15,925 more.
• $1.5 million: $66,000 today; $101,925. Pays $35,925 more, an effective rate of 6.8 percent.

The shape is the story. Every household under $500,000 gets the same small cut, capped at $325, because the lower brackets are tiny. Above $500,000 the increase is steep and immediate: the rate on the next dollar jumps from 4.4 to 7.4 percent. There is no phase-in.

Small businesses that file as pass-throughs (S corps, partnerships, LLCs) pay these individual rates on the owner's share. A Parker contractor or Castle Rock dental practice clearing $700,000 to its owner is in the 7.4 percent bracket on the top $200,000 of it.

What it means for the county as a whole

Nobody has published county-level numbers. The closest thing is PolicyEngine's open model of the measure by congressional district. For the 4th District, which is most of Douglas County plus the eastern plains, it estimates 87 percent of households pay less, 5.3 percent pay more, and the district as a whole sends about $177 million more to the state, with the average household's net income falling $688 because the increases on the top 5 percent outweigh the cuts for everyone else. For the 6th District (Aurora and Centennial, plus a small corner of northern Douglas County), 80 percent pay less, 1.5 percent pay more, and the average change is a $37 loss.

Douglas County's share of high earners is well above the 4th District average, so the county's own numbers would be more lopsided than those: more households above $500,000 than the district as a whole, and a larger net transfer out. That is the honest local frame. Most Douglas County households save a few hundred dollars. The county collectively pays a great deal more, because the people who pay more live here in unusual numbers.

Where the money goes

The ballot question says $2.7 billion a year, but that is the maximum state law requires Legislative Council Staff to print, padded for forecast error. The staff's actual estimate is $958.4 million in the 2026-27 budget year, which covers only half of tax year 2027, and $1.972 billion in 2027-28, the first full year; the campaign's own materials cite about $2 billion, which matches. The money must go to K-12 education, health care and early childhood care and education, on top of current spending rather than in place of it. PolicyEngine's model comes in far lower, about $1.1 billion, largely because it assumes high earners respond to higher rates. Treat the revenue as uncertain by a factor of nearly two. What is not uncertain is that DCSD, which is separately asking for a $54 million local override on this ballot (5A), would receive a share of whatever the state number is.

The lawsuit

On September 16, the Denver law firm Brownstein Hyatt Farber Schreck filed suit in Denver District Court on behalf of Michael A. Hancock, an Arapahoe County resident, arguing that 69 paid petition circulators never filed required training certificates and that their 9,849 signatures should be thrown out. That would drop the valid count from 130,938 to 121,089, below the 124,238 required. Michael Fields of Advance Colorado, which is running the competing Proposition 136, said his group is not funding the suit. Ballots print regardless; if a court disqualifies the measure after printing, we will report what happens to the votes already cast.

The other side of the ballot: Proposition 136

Advance Colorado's Proposition 136 caps the income tax at 4.4 percent, which would nullify 87's higher brackets. If both pass, the Blue Book says the general rule is that the measure with more votes controls where they conflict, but because 87 amends both the constitution and statute while 136 is statutory only, "the exact outcome is unclear" and the legislature or a court would have to resolve it. So a voter who wants the graduated tax should vote yes on 87 and no on 136; a voter who wants to keep the flat tax, the reverse. Yes on both hands the question to other voters, and possibly to a judge. What Proposition 136 means for Douglas County.

The case each way, honestly

For: 97 percent of Colorado filers, and most Douglas County households, pay less. The state's flat tax means a teacher and a hedge fund manager pay the same rate, and the money funds the schools this county keeps voting local overrides to prop up.

Against: Colorado's flat tax is in the constitution because voters put it there, and the state has grown faster than its neighbors partly on the strength of it. A jump from 4.4 to 7.4 percent at $500,000 is a steep step, and the people it hits, high-earning professionals and business owners, are the most mobile taxpayers there are. If enough of them file from somewhere else, the revenue is smaller than promised and the cut for everyone else is not.

Douglas County is where both arguments are strongest, because both kinds of taxpayer live here.

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