To run a Washington County tax map search, open the county’s Intermap tool and enter a street address, a tax lot ID, or an R number; the map will zoom to the parcel, outline its boundaries, and open an assessment subreport with ownership, sales, value, and improvement details. Oregon law requires every county assessor to keep these maps as public records, so the lookup is free.1Oregon State Legislature. Oregon Revised Statutes Chapter 308 – Assessment of Property for Taxation For older recorded surveys, plats, and section maps, the county runs a separate tool called Survey Explorer.
How to Search a Property in Intermap
Intermap accepts three main search inputs: street address, tax lot ID, or R number (the county’s internal account number).2Washington County, OR. Property Values and Improvements Both the tax lot ID and the R number appear on your annual property tax statement, usually near the top alongside the property address and legal description.
If you don’t have the tax statement in front of you, an address search is the simplest route. Use standard abbreviations for street types and keep the formatting clean. Owner-name search works too, but common names return long result lists, so pairing the name with a general location narrows things quickly.
What You’ll See on the Map
Intermap opens as a browser map centered on Washington County. After you search, it zooms to the parcel and highlights the boundaries. A sidebar lets you toggle data layers, including aerial photography that shows current structures and vegetation, and topographic overlays that show elevation changes.
The digital tax maps typically show parcel dimensions, public rights-of-way such as roads and utility easements, and annotations that reference recorded subdivision plats or deed documents. Total acreage or square footage is shown as well, and that figure feeds directly into the assessed value calculation.
Once a parcel is selected, look under Additional Information for the “Assessment & Taxation Information” subreport. It pulls together:2Washington County, OR. Property Values and Improvements
- General property information: owner name, situs address, legal description, and tax lot ID
- Sales and deed information: recent transaction dates, sale prices, and deed references
- Assessed value and real market value the county has assigned
- Improvement details: square footage, year built, and structural characteristics of buildings on the parcel
Built-in measurement tools let you estimate distances between boundary lines or the approximate footprint of a structure. They’re useful for quick planning, not for anything where legal boundaries matter.
What Tax Maps Legally Represent
Under ORS 308.245, each county assessor must maintain maps that outline the boundaries of every parcel subject to separate assessment, with the parcel’s tax lot or account number displayed on the map.1Oregon State Legislature. Oregon Revised Statutes Chapter 308 – Assessment of Property for Taxation The assessor may also mark code area boundaries, which show which taxing districts overlap a given parcel. Subdivisions and condominiums get separate diagrams that assign an account or tax lot number to each unit.
That is the whole legal purpose of a tax map: identifying parcels for assessment. It is not a boundary survey. Acting on it as if it were can lead to expensive disputes. If you need to establish an exact boundary line for a fence, a structure, or a sale, hire a licensed surveyor. Tax maps occasionally show parcel shapes that don’t match ground conditions, especially for older lots that predate digital mapping or for parcels described by metes and bounds. Those discrepancies are normal for assessment mapping, and they’re a reminder that a professional survey is the only reliable way to stake a boundary.
Survey Explorer for Older Records
Survey Explorer is a separate tool focused on recorded documents rather than live assessment data. It provides access to surveys, plats, government corners, benchmarks, section maps, county roads, and geodetic control points, mostly stored as PDFs that open at high resolution.3Washington County, OR. Survey Research Tool
One important limitation: the county stopped updating property boundary lines and city annexation information on its section maps in April 2012.3Washington County, OR. Survey Research Tool The section maps still show county road information, but current boundary or annexation data belongs in Intermap. Washington County benchmarks in this system use the NGVD 29 datum, which matters if you’re doing elevation work and need to convert to a more current vertical reference.
Reading the Two Values You’ll See
Intermap shows two numbers for every property: real market value and assessed value. In most states these would run close together. Oregon is different. Measure 50, passed in 1997, capped the annual growth of a property’s assessed value at 3 percent, regardless of how fast the real market value climbs. The assessed value started as a 10 percent reduction from each property’s 1995–96 real market value and has grown from that baseline ever since.
Your tax bill is based on the assessed value, not the real market value. In fast-appreciating areas the assessed value may sit well below what the property would sell for today. If the real market value ever drops below the assessed value, as happened broadly in the 2008–2010 downturn, the county must reduce the assessed value to match, and that lower figure doesn’t snap back up when the market recovers. It resumes growing at 3 percent per year from the reduced amount.
Getting Certified Physical Copies
A screenshot or PDF export from Intermap is fine for personal research and informal planning. Mortgage lenders, title companies, and parties in boundary disputes sometimes need documents that carry the assessor’s official seal instead. Physical copies are requested from the Washington County Assessment and Taxation office in person or by mail, and the department can be reached at 503-846-8752 for recording and general inquiries.4Washington County, OR. Assessment and Taxation
Fees and processing times vary with map size and whether certification is required, and turnaround usually runs several business days. Certified copies carry weight in legal proceedings and appraisal reviews that a printout wouldn’t. Call ahead if the request is time-sensitive.
If the Map or Value Looks Wrong
Errors on tax maps do happen. A parcel boundary might not reflect a recorded lot line adjustment, or an account number might reference the wrong legal description. Start with the Washington County Assessment and Taxation office. Many errors, especially outdated ownership records or missing lot splits, can be resolved at the county level.
Beyond the county, Oregon’s Department of Revenue has authority under ORS 306.115 to order corrections to assessment and tax rolls, including clerical and valuation errors. The department can correct the current tax year’s roll, and in some cases the two immediately preceding years, if a correction is necessary to bring the roll in line with applicable law.5Oregon State Legislature. Oregon Revised Statutes Chapter 306 – Administration of Property Tax Laws Before ordering a correction the department holds a conference to review the facts.
Correcting a factual error is separate from disputing what the property is worth. If you think the assessed or real market value shown for your parcel is wrong, Washington County runs a no-fee appeal through the Property Value Appeals Board. Petitions must be postmarked or delivered to the county clerk’s office between late October, when tax statements are mailed, and December 31 of the same year, with the deadline extending to the next business day if December 31 falls on a weekend or holiday. Hearings are informal, you don’t need an attorney, and you can either appear or let the board decide on your written petition. Hearings run from the first Monday in February through April 15, and the clerk’s office will notify you of your scheduled date.6Washington County, OR. Property Value Appeals The board can only consider the current tax year.
Filing a correction request doesn’t prevent you from filing a value appeal, and vice versa. When preparing an appeal, Intermap earns its keep: you can pull nearby comparable parcels and use their sales and assessment data to show that similar properties carry lower assessed values relative to their real market values.