Can my property taxes go up if I appeal in California?

California is one of the few states where a homeowner-initiated appeal can result in a higher assessment. Under Cal. Rev. & Tax. Code §1610.8, the county board's job is to equalize the assessment by determining the property's full value — and the statute expressly authorizes the board to reduce or increase an individual assessment. The state BOE assessment appeals page describes the board as an independent body that decides value, not one that can only lower it.

In practice the risk is real but bounded:

• The board cannot raise your value above your factored base year value ceiling (the Prop 13 base plus up to 2%/year) for a regular Prop 8 dispute under Cal. Rev. & Tax. Code §51 — the lesser-of rule still caps the enrolled value at the factored base year value. So an appeal of a temporary decline-in-value reduction can be "restored" toward that ceiling, but not beyond it.
• The board can enroll a higher value when the assessor properly raises the issue: §1610.8 puts the burden of proof on the assessor whenever the assessor seeks a value higher than the one on the roll, which signals that an upward result is a recognized outcome.

Before filing, bring credible comparable sales as of the January 1 lien date and a realistic opinion of value. If your evidence is weak and the current roll value is already below market, an appeal can invite the assessor to argue for an increase. When the case is solid — especially for an owner-occupied single-family home where §1610.8 shifts the burden to the assessor — the downside risk is low. The state's Publication 30 advises homeowners to prepare evidence accordingly.