Glossary
Colorado terms, defined.
The 18 words that show up on Colorado value notices, tax bills, well permits, closing statements, and license receipts. Each one comes with the page that goes deeper and the official source behind it.
Actual value
The county assessor's estimate of what your property is worth. It is the number printed on your notice of valuation, and it is the part you can appeal if it looks wrong. Colorado does not tax it directly — the state first turns it into a smaller number called the assessed value.
See Property tax estimator · Official source: Colorado Division of Property Taxation
Assessed value
The smaller number Colorado actually taxes. The state multiplies your home's actual value by a residential assessment rate to get it. The mill levy is then applied to this number, not to the full value of the home.
See Property tax estimator · Official source: Colorado Division of Property Taxation assessment rates
Augmentation plan
A court-approved plan to put replacement water back in the stream for the water a property uses. In over-used basins — much of the Front Range and the major river valleys — you usually cannot get a permit for a non-exempt well unless an augmentation plan replaces what the well depletes. If a property comes with one, treat it as an obligation to verify, not a footnote.
See Water and wells · Official source: Colorado Division of Water Resources
Defensible space
The cleared, managed area around a home that slows a wildfire — clearing brush and hardening the house against embers. Insurers pay attention to it: mitigation can lower the risk and may help you get covered, but every company sets its own rules, so it does not guarantee a lower premium. Some HOAs and counties require the clearing.
See Wildfire and insurance · Official source: Colorado State Forest Service wildfire mitigation
Documentary fee
Colorado's small statewide recording charge when a property sells: one cent for every $100 of the price, paid to the county clerk and recorder — about $65 on a $650,000 home. It is the closest thing Colorado has to a transfer tax. TABOR barred new transfer taxes in 1992, so only a dozen grandfathered mountain and resort towns still charge a real one.
See Closing costs · Official source: Colorado documentary fee (C.R.S. 39-13-102)
GMU (Game Management Unit)
A numbered chunk of Colorado's hunting map. The state is split into hundreds of them, and rules, tags, and seasons change from unit to unit. Your tag is usually good only in specific GMUs, so always know which unit you are standing in — CPW's free Hunting Atlas shows the units, public land, and access.
See The hunting guide · Official source: CPW Where to Hunt + Hunting Atlas
Habitat Stamp
A small annual purchase required with most Colorado hunting and fishing licenses for ages 18–64 — one per license year, normally added automatically to your first qualifying license. It funds wildlife habitat and the public-access easements that have opened land and river miles to the public. It is the detail people most often forget, so glance at your cart.
See Hunting and fishing basics · Official source: CPW Habitat Stamp
Metro district
A type of special district often used to finance the roads, water, sewer, and parks in newer development. The district borrows by selling bonds, then pays the loan back with property taxes from the homes inside its lines — sometimes for decades. It is a local government with taxing power, not an HOA, and it can add a large mill levy even when a nearby older neighborhood pays much less.
See Metro districts · Official source: Colorado Property Tax Entities and Mill Levies map
Mill levy
The property-tax rate. One mill is $1 of tax for every $1,000 of assessed value, so a 75-mill total levy means about $75 for each $1,000. One address can sit inside many taxing districts at once — county, school, city, fire, library, sanitation, metro district — and each adds its own mills, so always check the full stack for the exact address.
See Property tax estimator · Official source: Colorado Property Tax Entities and Mill Levies map
Notice of valuation
The letter the county assessor mails with your home's value. It shows the actual value the county set, how the property is classified, the details on file, and the protest deadline. Colorado's appeal window is short — a spring window, with many counties setting an early June deadline — so go by the date printed on the notice.
See Assessment appeals · Official source: Colorado county assessor directory
Prior appropriation
Colorado's water-rights system: first in time, first in right. Whoever first put water to a beneficial use — and got a court decree — holds the senior right, and in a dry year senior rights are filled before junior rights get a drop. A water right is its own piece of property that can be bought and sold apart from the land, which is why owning land does not mean owning the water on or under it.
See Land, mineral and property rights · Official source: Colorado Division of Water Resources
Residential assessment rate
The small slice of a home's actual value that gets taxed. Since 2025 Colorado uses two residential rates: about 6.25% for local-government mills and 7.05% for school-district mills. Each rate applies to its own share of the mills, and the two parts add together to make the bill.
See Property tax estimator · Official source: Colorado Division of Property Taxation assessment rates
Special district
A local government layer that taxes for a specific service — fire, library, sanitation, parks, or infrastructure. A single subdivision can sit inside several districts at once, and each one adds its own mills or sales tax. It is a big reason the tax answer can change across the street.
See Local taxes and TABOR · Official source: Colorado Property Tax Entities and Mill Levies map
Specific ownership tax (SOT)
Colorado's annual vehicle tax, charged with your registration in place of personal property tax. It is based on the vehicle's original value and its age — not what you paid or what it is worth today. The first year runs 2.1% of taxable value and the rate steps down as the vehicle ages, which is why a newer, pricier car costs far more to register than an old economy car.
See Vehicle registration estimator · Official source: Colorado DMV — vehicle taxes and fees
Split estate
When the surface of a piece of land and the minerals under it belong to different owners — common in Colorado's oil, gas, and mining country. The mineral estate is generally 'dominant,' so the mineral owner may be able to use a reasonable amount of your surface to reach their minerals, within limits. What you actually own only shows up in the recorded documents for the exact parcel.
See Land, mineral and property rights · Official source: Energy and Carbon Management Commission (ECMC)
TABOR
Colorado's Taxpayer's Bill of Rights. It makes governments ask voters before raising most taxes, and it limits how much revenue they can keep — collect more than the limit and they often have to refund the extra. It shapes how governments ask for money, but it does not make every bill low: voters can approve new taxes, districts can add their own, and assessed values can rise on their own.
See Local taxes and TABOR · Official source: Colorado Department of Revenue
Use tax
The tax you owe when you buy something — like a car or building materials — without paying local sales tax at the register. Colorado cities and counties set their own sales and use tax rates, so the amount depends on your exact address.
See Local taxes and TABOR · Official source: Colorado Department of Revenue
Well permit
State permission for a water well, issued by the Colorado Division of Water Resources. The permit says what the water can be used for — many small-acreage 'exempt' wells are household-use-only, meaning no watering of lawns, gardens, or livestock, even though it is your well. Read the actual permit before you count on the water, and know that dividing the land can change an exempt well's status.
See Water and wells · Official source: Colorado Division of Water Resources
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