Check the assessment year before filing
Last checked September 5, 2026 against the official sources linked below. This guide covers filings during 2026; the assessment roll or resulting tax bill may belong to a later year. Check the current official notice before filing.
A lower market value may leave assessed value unchanged
Oregon distinguishes real market value (RMV), maximum assessed value (MAV) and assessed value (AV). Clackamas explains that AV is the lower of RMV and MAV. If a reduced RMV remains above MAV, the assessed value stays the same.
For example, suppose RMV is $650,000 and MAV is $400,000. Reducing RMV to $550,000 still leaves AV at $400,000. That arithmetic alone does not establish a tax saving. Ask how the change affects the actual bill, including any tax compression, before treating the market-value reduction as a cash benefit.
Read the fall statement and property detail together
The filing period begins after tax statements mail, and the county publishes December 31, 2026 as the closing date. Use the statement to identify the tax account, values and year. MAV may need to be retrieved from the county property detail page.
For Oregon City, Lake Oswego, West Linn or rural Clackamas property, compare the same type of home and market setting. Location names alone do not account for waterfront, acreage, slope, renovation or usable building area.
Show why your requested value is supported
The county's evidence guidance includes a relevant appraisal, comparable sales, inventory errors and documented repair costs. Your packet should connect the strongest exhibits to the January 1, 2026 value under review.
Include a short summary of the disputed value and what you want changed. For each comparable, explain its similarities and material differences. A repair estimate is most helpful when photographs and property facts show what existed at the valuation date.
Prepare the copies and representation before delivery
Clackamas asks for five copies of the petition and evidence. Confirm that the owner or an eligible representative has signed the correct form. Hand delivery must arrive by 5 p.m. on December 31; mailed petitions need a qualifying USPS postmark by December 31.
The county schedules the Board's 2027 session from February through no later than April 15. State your availability as requested, keep a complete copy and prepare written evidence even if you do not plan to attend. Confirm Homespring's available support before relying on it to file or appear.