The 90-Day Rule That Disqualifies Your Best Comparable Sales

Homeowners lose winnable appeals on this one rule. They gather the most recent sales they can find — the freshest data, the lowest prices, the clearest evidence the market fell — and walk into a hearing where most of it is inadmissible.

What §402.5 says

Revenue & Taxation Code §402.5 governs comparability. To be considered comparable, a sale must be sufficiently near in time to the valuation date, sufficiently near in location, and sufficiently alike in character, size, situation, usability, and zoning.

Then it draws one hard line: "near in time to the valuation date" does not include any sale more than 90 days after the valuation date.

Note the direction. The statute caps how far after the valuation date a sale can occur. It sets no numeric limit on how far before — that's governed only by the general "sufficiently near in time" standard, and by what an appraiser or board will find persuasive. Six months prior is ordinary; two years prior invites the question of what changed in between.

Valuation date, not lien date

This trips people up, and the statute itself used to. A 2014 amendment (AB 1143) replaced "lien date" with "valuation date" precisely to stop the confusion — because they're only the same thing sometimes.

Type of assessment	Valuation date	90-day cutoff
Regular annual assessment (incl. Prop 8)	January 1 lien date	≈ April 1 of that year
Change in ownership / purchase	Date of transfer	90 days after closing
New construction	Date of completion	90 days after completion

So if you're appealing your annual assessed value, your usable window ends around April 1. If you're appealing a base year value from a purchase that closed in October, your window runs to roughly the following January — a completely different set of sales. (Appealing a value set at purchase.)

Why this hurts most in a declining market

Run the calendar for a typical Prop 8 appeal on the current roll:

• Valuation date: January 1
• Last usable sale: ≈ April 1
• You receive your notice and start working: July or August
• Your county's deadline: September 15 or November 30 (which one depends on your county)

Every sale from April onward — four to seven months of the freshest, and in a falling market the lowest, transactions — cannot be used. Meanwhile a public listing site sorts by "most recent" and shows you exactly the sales you can't cite.

The rule is symmetric in principle, but in a declining market it systematically favors the assessor: the sales closest to your valuation date are from a stronger market than today's.

How to work within it

Anchor on the valuation date and search backward. Identify your valuation date first, then look at the window ending 90 days after it. For a regular assessment, that's roughly the six months before January 1 plus January through March.

Weight the closest sales most. A February sale for a January 1 valuation is worth more than a July sale from the prior year, even though both are admissible.

Use the pre-period to establish trend. Sales from the preceding six to twelve months are admissible and let you show direction. A board that sees a consistent downward trajectory through your valuation date will read the closest sales as part of a pattern rather than as outliers.

Don't smuggle in later sales as "market context." Some filers cite post-cutoff sales as background rather than comparables. Assessors know the rule, and it costs you credibility. If you want to reference conditions after the valuation date, be explicit that you're not offering them as comparables — but the honest answer is usually to leave them out.

Remember the other §402.5 factors. Timing is necessary, not sufficient. A sale two weeks from your valuation date, three neighborhoods away, of a different property type, isn't comparable. Character, size, situation, usability, and zoning all still have to line up — which for condos means floor, view, and parking too. (Choosing comps that hold up.)

If the timing genuinely defeats you, consider next year. When your valuation-date window predates the decline you're trying to prove, the honest case may be for the following lien date, when the fallen market sits inside the usable window. Prop 8 reductions are annual, so a year you can't win doesn't foreclose the next. (How Prop 8 works year to year.)

Washington is different

If you're appealing in Seattle or Issaquah, don't apply this rule. Washington has its own framework — the assessor's value is presumed correct, and the January 1 valuation date operates under different evidentiary standards. (The King County process.)

Why we built the screen in

Filtering sales by valuation date and property characteristics simultaneously is tedious and easy to get wrong, and getting it wrong is the difference between a hearing and a dismissal. CompFinder applies the §402.5 window automatically for SF, Oakland, and San Jose properties and screens on the comparability factors, so what you present is admissible before you start arguing about value.