PITTSBURGH — Allegheny County Executive Dan Onorato said he will appeal a court-ordered property reassessment plan to Commonwealth Court.

A judge last week ordered the county to split itself into four regions, with each region performing reassessments every four years. Wettick's plan stems from a state Supreme Court decision that says the county violated the state constitution by valuing properties on the "base year" of 2002.

But Onorato said other counties do the same thing and the answer is for the Legislature to come up with a uniform reassessment system across the state. Butler County is one of the counties that uses a base year of 1969 to derive assessment values.

Opponents of a base-year system say homes in declining neighborhoods become overvalued while those in nicer neighborhoods are undervalued as time passes.