Property Tax Appeal Evidence: Comp Sales, Photos, and the Petition Packet

A Washington property tax appeal lives or dies on three things: 3-5 strong comparable sales, dated condition photos, and a clean petition packet (Form REV 64 0075 plus attachments). Get those right and the County Board of Equalization (BOE) usually grants at least a partial reduction. Get them wrong — or skip one — and the assessor's number stands. This is the working manual for assembling the evidence.

The mechanics of the appeal — deadlines, statutes, hearing logistics — are covered in the complete WA property tax appeal guide. This guide goes one level deeper on the part that actually decides the outcome: the evidence packet itself.

Why the BOE decides on evidence, not arguments

The County Board of Equalization is a quasi-judicial body. Three appointed county residents — required to be independent of the assessor under RCW 84.48.010 — review your petition, hear the assessor's response, and decide whether the assessed value exceeds true and fair value. They are not deciding whether your taxes feel high. They are deciding a factual question: what is this property worth on January 1 of the assessment year?

The assessor walks into that hearing with a mass-appraisal model output, recent sales the model relied on, and a brief narrative defending the assessment. That's their evidence. Your job is to walk in with a stronger case for a lower number.

Homeowners who arrive with three to five well-chosen comps and a small set of dated condition photos win meaningfully more often than homeowners who arrive without them. Homeowners who try to argue the assessment without evidence — "the market is softer," "my neighbor's taxes went up too," "I can't afford this" — lose almost every time. The BOE has no statutory authority to reduce based on hardship. They reduce based on overvaluation, and only when overvaluation is shown.

The three pillars of a winning appeal packet

Strip a successful BOE petition to its load-bearing parts and three things remain. Everything else is supporting material around them.

Pillar 1 establishes the value range. Pillar 2 explains why your home should land at the bottom of that range, not the top. Pillar 3 makes sure the BOE actually receives, considers, and is procedurally able to act on your case. Skip any one of them and the petition gets denied even when the underlying merit is real.

The remainder of this guide is built around those three pillars in order.

Comparable sales: the criteria that move BOE hearings

Five rules govern which sales count as comps and which don't. Apply all five — the BOE applies them, and so does the assessor.

Rule 1: Sold within 12 months of the assessment date

Washington assesses property at its true and fair value as of January 1 of the assessment year (RCW 84.40.020). For a 2026 assessment, that's January 1, 2026. Comps should be sales that closed within roughly 12 months of that date — ideally 6 months on either side. Stretch to 18 months only if the neighborhood has very low turnover, and adjust for market movement using a published index. Sales older than 18-24 months get heavily discounted by the BOE regardless of how comparable the property is.

Rule 2: Within 0.5-1 mile, or same neighborhood/subdivision

The closer the better. Same street is ideal. Same subdivision or HOA is excellent. Same neighborhood (defined by school attendance area, micro-market, or named area) is acceptable. Cross-neighborhood comps are weak unless the neighborhoods are demonstrably comparable by every other metric. A 2,400 sqft home two miles away in a different school district is not a comp, even if the square footage matches.

Rule 3: Similar square footage (within ~15%)

A 2,000 sqft home is not comparable to a 2,800 sqft home, even on the same street. The BOE's working tolerance is roughly 15% — for a 2,400 sqft subject property, comps in the 2,040-2,760 range are inside the band; outside that, you'll need to do explicit per-square-foot adjustments and the BOE may discount the comp.

Rule 4: Similar lot size

A 6,000 sqft lot home is not comparable to a 16,000 sqft lot home. In urban infill neighborhoods, lot size variance is small and the rule rarely binds. In suburban or semi-rural parts of King, Pierce, Snohomish, and Kitsap counties, lot size varies widely and matters a lot — a half-acre home is not a comp for a quarter-acre home in the same subdivision.

Rule 5: Similar age and construction quality

A 1985 ranch is not a comp for a 2018 new build, even if the square footage matches. Match the year built within roughly ±15 years for older homes (where construction era matters less) and ±5 years for anything built after 2000. Match the construction quality grade the assessor uses (your Change of Value notice or the parcel viewer shows it — typically Average, Good, Very Good, Excellent).

Where to find comps for free

The county assessor's website is both the best source and the most underused — that's exactly where the assessor pulled comps from when setting your value, and the BOE treats county records as the gold-standard source. Start there before anything else.

County assessor portals (start here)

• King County — eMap (gismaps.kingcounty.gov/parcelviewer2) and the Assessor's Property Search. Click any nearby parcel to see sale date, sale price, square footage, and characteristics.
• Pierce County — PALS (pals.piercecountywa.gov). Same workflow: parcel view shows sales history.
• Snohomish County — Property Search (snohomishcountywa.gov/Assessor). Sales records by parcel.
• Other WA counties — most have a parcel viewer or property search tool linked from the county assessor's homepage. The data is public.

Real estate sites (cross-check)

• Redfin sold filter — filter recently sold homes by date range, square footage, and beds/baths. Click through to listing detail for photos and condition notes.
• Zillow sold filter — similar workflow. Useful for cross-checking that a sale was arms-length (estate sales and family transfers often show up in remarks).

Always cross-check the sale price between the county record and the real estate site. They should match. If they don't, the county record wins — that's the official record of the recorded sale, and that's what the BOE will use.

Building the comp-sales spreadsheet

The comp-sales spreadsheet is the single most important attachment in your packet. It transforms a list of addresses into a defensible value estimate. Use these columns:

• Address (street + city)
• Sale date (month/year)
• Sale price
• Square footage
• Sale price per sqft (calculated: price ÷ sqft)
• Lot size (sqft)
• Year built
• Bed / bath
• Distance from your property (miles, to one decimal)
• Source URL (county parcel page or Redfin/Zillow listing)

At the bottom: average sale-price-per-sqft across the 3-5 comps. Multiply by your home's square footage to derive a fair-market estimate. That estimate, adjusted for any condition factors documented in your photos, is the value you'll request.

Worked example — Renton, 2026

Subject property: 2,300 sqft 4-bed/2.5-bath built 1998 on a 7,200 sqft lot. Assessed at $825,000.

Average comp $/sqft = $312.50. Applied to subject sqft (2,300) = $718,750 indicated value. Subject is currently assessed at $825,000 — a $106,250 over-assessment, or 14.8% above true and fair value. With dated photos showing an original 1998 roof and un-remodeled kitchen (which Comps 2 and 4 don't share), an additional $15-20K downward adjustment is defensible, bringing the requested value to roughly $700,000.

Photo evidence: what to shoot and how to label

Photos do something the comp spreadsheet can't: they show the BOE why your home is at the lower end of the comp range, not the upper end. Three categories.

Category 1: Condition defects

The interior and exterior issues that reduce your home's value relative to the comps. Date-stamp them on your phone (most camera apps embed the date automatically; verify yours does, or include a newspaper or dated piece of mail in the frame). Examples:

• Cracked foundation, settling, or visible structural issues
• Water damage, staining on ceilings or walls, mold/mildew evidence
• Original (un-remodeled) kitchen or bathrooms — especially if older than 20 years
• Roof issues (visible wear, missing shingles, moss, age — pair with a contractor estimate if you have one)
• Aging or undersized HVAC, original windows, original electrical panel
• Deferred maintenance — peeling paint, rotted siding or trim, deck damage

Category 2: External negatives

Site-level factors that aren't visible in the parcel data but reduce market value:

• Busy road frontage (traffic noise — shoot toward the road from the property)
• Power lines, transmission towers, or commercial structures adjacent to the lot
• Easements crossing the lot (utility, access)
• Downhill drainage or flood-prone areas
• Adjacent commercial use, freeway proximity, rail line

Category 3: The comp homes

Drive-by exterior shots of your 3-5 comp homes — pulled from Google Street View if recent, or shot in person. The point is to give the BOE a visual basis for comparison: "Comp 2 has a new roof and updated exterior; my home does not." A picture compresses a paragraph of explanation.

Labeling — every photo, every time

A photo without a caption is half-evidence. For each image, include:

• Date the photo was taken
• Location (subject property, address of comp, GPS if useful)
• Description in one sentence ("Original 1998 roof, moss accumulation visible at south slope, no replacement in records")

Print photos at a usable size (4x6 minimum, 5x7 better) and embed captions directly underneath. A clean printed photo packet looks like evidence; a folder of unlabeled phone photos looks like a homeowner who didn't take it seriously.

The BOE petition packet — exactly what to file

Here is the literal stack of paper (or PDF set, for counties that accept online filing) you submit. Use this as a checklist.

Filing deadline

Under RCW 84.40.038, file by the later of July 1 of the assessment year or 60 days after the county mailed your Change of Value notice. For most homeowners, July 1 is the operative deadline. The full deadline mechanics — including the RCW 84.40.038(1)(b) "good cause" exception — are covered in the master appeal guide.

How to submit

King County accepts online submissions through the BOE eFile system. Pierce and Snohomish accept both online and mail. Smaller counties typically require mail submission with three copies (one for the BOE, one for the assessor, one for your records). If mailing, use certified mail with return receipt requested — the postmark and signed receipt are your proof of timely filing.

The 1-page narrative: a template

The narrative letter is the BOE's first read of your case. Keep it to one page. Four short paragraphs, in order: what you propose, the comp summary, the condition factors, the requested action. Plain language, specific numbers, no rhetoric.

Plain. Numeric. Specific. The BOE reads dozens of these in a hearing cycle — yours stands out by being clear, not by being clever.

Common evidentiary mistakes that lose appeals

Six recurring mistakes account for most evidence-based denials. Each one is avoidable.

1. Using assessed values of comps instead of sale prices. The assessment is what the assessor thinks the comp is worth — that proves nothing. The sale price is what a buyer actually paid. Only sale prices count as comp evidence.
2. Using comps from before the assessment date. Sales that closed more than 12 months before January 1 of the assessment year get heavily discounted. Sales older than 18-24 months are usually thrown out entirely.
3. Using comps too far away. Cross-neighborhood comps require explicit justification. A 2,400 sqft home three miles away in a different school district is not a comp, no matter how close the square footage matches.
4. Photographing without dates. An undated photo could be from any year. The BOE wants current condition evidence, not historical. Confirm your phone embeds dates in EXIF, or include a dated newspaper or piece of mail in each frame.
5. Arguing taxes are too high. The BOE has no authority to reduce based on tax burden, hardship, or rate increases. They reduce only when assessed value exceeds true and fair value. Stay on the value question.
6. Arriving without the printed packet. Even for telephonic or video hearings, the BOE expects to have the packet in front of them. If you only submitted electronically, bring printed copies anyway in case of system issues. For in-person hearings, bring three sets — one for you, one for the BOE, one for the assessor's representative.

What happens at the hearing

The hearing itself is short and structured. Most residential BOE hearings run 15-30 minutes total.

1. Opening (2 min) — BOE chair confirms attendance, explains process, swears in parties if required.
2. Your presentation (5-10 min) — walk through your comps, the indicated value calculation, the condition factors, and the requested value. Stick to the narrative letter as your script.
3. Assessor response (3-5 min) — the assessor's representative defends the original assessment, often with their own comp set or model output.
4. Clarifying questions (2-5 min) — the three-member board asks both parties for clarification on specific points.
5. Decision — the BOE may decide at the hearing, or take it under advisement and issue a written decision within 45 days.

Tone: factual, brief, and on the value question. No emotional appeals, no comments about your tax burden, no commentary on the assessor's competence. The BOE is comparing two valuation cases — make yours the better-evidenced one and let the evidence do the work.

For more on the hearing tactics that help and the assessor arguments to anticipate, see the complete WA property tax appeal guide. If your assessment increased sharply this year, the why-it-went-up guide walks through the most common drivers and how each affects your evidence strategy. And if you're 61+ or have a qualifying disability, check the senior/disabled exemption guide first — the exemption may eliminate the need to appeal at all.

Frequently asked questions

Related reading: How to Appeal Your WA Property Tax (master guide) · Why Did My Property Tax Assessment Go Up? · WA Senior & Disabled Property Tax Exemption · WA Property Tax Appeal Tool

About this guide: Written by the Claim Maximizer team. RCW citations and Form REV 64 0075 references verified against the Revised Code of Washington and Washington Department of Revenue forms library as of April 2026. Not legal advice — we are not a law firm. For commercial property appeals, properties over $2M, or cases involving litigation, consult a Washington-licensed property tax consultant or attorney.