words that say Thurston County

Glossary of Terms

Credits: This page is based on a glossary from the City of San Diego. It has been modified for Thurston County.

Jump to:

A, B, C, D, E, F, H, I, M, N, O, P, R, S, V, Z.


Assessed Value (AV) is the amount used by the county tax assessor to value real property for tax purposes. Assessed value is usually the market value of the property. Assessed value multiplied by the tax rate is the property tax.


Base Zone is a zone that defines permitted uses, setback requirements, and other requirements for development for properties located within the zone. Some neighborhoods, though, have unique characteristics or challenges. In these areas, overlay zones are sometimes established and put down on top of (overlapped) the base zone. Click here for more information.

Building Code - See International Building Code below.

Buffer is a restricted area adjacent to a specified critical area (wetland, river, stream, habitat area) where new construction is generally prohibited -- ie, it is a preserved area of land that protects a critical area from the affects of development.


Certificate of Occupancy is a certificate that is issued by the zoning officer to indicate that, after construction of a building has been completed or a use in an existing building has been changed, the purpose for which the building was constructed is being carried out in accordance with the terms of the zoning ordinance.

Comprehensive Plan is Thurston County's master blueprint for land use. It guides the physical, social, economic, and environmental development of Thurston County, including studies of land use, circulation, etc.. A Comprehensive Plan is usually a composite of mapped or written development policies for the county which is adopted by the Board of County Commissioners after a public hearing. The Comprehensive Plan is implemented largely through zoning controls and land-use regulations. Click here for more information.

Conditional Use Permit (CUP) is given to certain classes of land use the are not permitted by right in some or all zones of the county, but are nevertheless recognized as being desirable to the full function of the county under appropriate circumstances. The purpose is to provide a means whereby proposals for such land uses may be examined on a case by case to determine whether, and under what conditions, these uses may be approved at a given site.

Critical Areas Ordinance is a set of regulations that govern how land is developed in environmentally sensitive areas and in areas where development would pose a threat to humans or wildlife. Critical areas include important fish and wildlife habitat areas (prairies, rivers, streams); wetlands; aquifer recharge areas; frequently flooded areas; and geologically hazardous areas. The state Growth Management Act requires protection of these areas. Click here for more information.


Determination of Significance/Non-Significance - see SEPA below.

Development Rights is a term applied to a broad range of less-than-fee-simple ownership interests mainly referring to easement. Thus the owner can retain complete or absolute (fee simple) rights to his her land use and sell the development rights to another. The owner would keep the title but agree to continue using the land as it had been used in the past with the right to develop resting in the holder of the development rights.

Drainage Manual is the document that contains regulations developers must follow to help prevent and control stormwater runoff and erosion that results from their project. Click here for more information.

Downzoning refers to a change in the zoning classification of land to a classification
permitting development that is less intensive or dense, such as from multifamily to single-family or from commercial or industrial to residential. A change in the opposite direction is called upzoning.


Energy Code is a state-written, state-specific code that Thurston County enforces. It sets minimum levels of energy efficiency for building projects. Click here for more information.


Flood Hazard Areas - See Special Flood Hazard Areas below.


Hearing Examiner is an attorney appointed by the Thurston County Board of Commissioners to provide quasi-judicial proceedings for land use issues that is fair, efficient, open and accessible to all citizens. Examples of land-use cases, include SEPA, zoning, critical areas, urban growth areas, plats and subdivisions and shorelines. Click here for more information.

Highest and Best Use for property will bring its owner the greatest profit it offered for sale. In theory the economics of the real estate market establish a maximum value for each parcel of land at any given time. Except in developed areas or along transportation corridors where there is pressured to develop this “highest and best use” is likely to be agricultural or residential. For example, while a gas station built on particular site might give the owner the greatest return zoning might only allow for single-family homes. Thus one purpose of zoning is to prevent the “highest and best use” where it is inappropriate.


Infrastructure consists of public improvements which support development, including street lighting, sewers, flood control facilities, water lines, gas lines, telephone lines and more.

International Building Code is a model building code developed by the International Code Council. Most states, including Washington, have adopted the IBC Code but with a few state-specific amendments. Local jurisdictions, such as Thurston County, also amend the state-adopted version slightly to fit local circumstances. See our Building Code page for more information.


Market Value is what a willing seller could reasonably expect to receive if he/she were to sell the property on the open market to a willing buyer.


Nonconformities or "non-conforming uses" relate to lots uses of lots and structure and characteristic of uses that are prohibited under the terms of the zoning ordinance but were lawful at the date the ordinance’s enactment. They are permitted to continue or are given time to become conforming. The continuation of such Nonconformities is based on the principal that laws cannot be applied retroactively unless there is a compelling reason - such as imminent danger to health - to do so.


Open Space Tax Program encourages property owners to preserve open space and farmlands by allowing them to apply to have their property assessments based on "current use" values rather than "highest and best use." Under state law, property taxes are automatically based on "highest and best" use of the land. Click here for more information (external link).

Overlay Zones - See Base Zones above.


Performance Standards state the minimum or maximum allowable limit on the effects or characteristic of a use. A building code for example, might specify a performance standard referring to the fire resistance of a wall, rather that specifying the construction materials. Performance standards in zoning might describe allowable uses with respect to smoke, odor, noise, heat vibration, glare, traffic generation, visual impact, and so on.

Permitted Use is a use by right that is specifically authorized in a particular zoning district. It is contrasted with special permit or conditional uses that are authorized only if certain requirements are met and approved by the county.

Planning Commission is a group of citizens that acts in an advisory capacity to the Board of County Commissioners. Click here for more information (external link).

Principal Use is the main use of land or structures as distinguished from a secondary or accessory use. A house is a principal use in a residential area: a garage or pool is an accessory use. Zoning ordinances will often establish a general rule that only one principal structure or use will be permitted on each lot.


Residential Zone – See Zoning

Rezoning applies to both zoning amendments and zoning revisions. It is the commonly accepted term that refers to any change in the zoning ordinance. Rezoning can apply to a small area or a large portion of the county. 


SEPA (State Environmental Policy  Act) is a state policy that requires state and local agencies to consider the likely environmental consequences of a proposal before approving or denying the proposal. Thurston County requires certain types of land-use applications to go through the SEPA process, which involves submitting an environmental checklist. Thurston County may make three types of determinations: a Determination of Non-Significance, a Mitigated Determination of Non-Significance, and a Determination of Significance.  Click here for more information.

Setback refers to the distance a structure must be from the edge of a lot. Setbacks are established along front, rear and side property lines and some easements. The width of setbacks depends on how property is zoned. See "Zoning" below.

Shoreline Master Program is a set of policies and regulations that govern governs uses and activities on marine (salt water) shorelines, lakes and rivers throughout the county. Click here for more information.

Special Use Permits allow uses to be permitted in a zone in which they are not automatically allowed. For example, a special use permit is required for mineral extraction activities (gravel mines, asphalt plants). Click here for more information.

Special Flood Hazard Area is any area:

  • Subject to a base of one-hundred year flood (areas of special flood hazard are shown on a flood hazard boundary map or Flood Insurance Rate Map as Zone A, AO, A1-30, AE, A99, AH, VO, V1-30, VE, V).
  • High Ground Water Flood Hazard Areas Resource Map on file with the Resource Stewardship Department.
  • Highest known recorded flood elevation.

Click here for more information.


Variance is a device that grants a property owner relief from certain provisions of a zoning ordinance when, because of the particular physical surroundings, shape, or topographical condition of the property, compliance would be a hardship upon the owner. A variance may be granted for example to reduce setback requirements.


Zoning is a legislative means of ensuring that land uses of community are property situated in relation to one another. The Zoning Ordinance regulates how land may be used and developed. It outlines the kind of activity (uses) that can be established (permitted) in each zone. Zoning influences the kind of neighborhood people live and work in. Zoning also influences the development potential and preserves the value of property. Zoning controls the type and intensity of development so that property can be adequately serviced by public facilities such as streets, schools, parks, water, and public services. Click here for more information.

Zoning Amendments can change or revise the zoning ordinance or map. This must be done by legal public process.


Contact Us

Please click here for contact information.


This page last updated: