There are plenty of reasons for concern about Oahu’s skyrocketing real property valuations. Double-digit increases well above the inflation rate threaten to squeeze homeowners — many on fixed incomes — already struggling to make ends meet.

Most disturbing is a suggestion by City Council Budget Chairman Calvin Say that the high assessments were the result of pressure from lawmakers or public worker unions to increase the revenue pool for collective bargaining pay raises.

The Honolulu Star-Advertiser reported that Say noted without the valuation increases, the Council would have to increase the property tax rate to cover pay raises.

“If you and I were paying $100 today on our home, and it went up to $140, that $40 assessment increase on the real property tax values has been earmarked for collective bargaining,” he said.

When asked whether lawmakers or union officials had a hand in pushing for higher property values, Say said, “I believe so.”

If politicians and unions in fact put such a thumb on the scale, it’s a corrupt act that should be investigated by city and state prosecutors.

Valuations by the city’s Real Property Assessment Division are supposed to be objective, honest and fair.

If the mayor and City Council want more revenue, they’re supposed to get it by adjusting the tax rate, a transparent process that requires ample opportunity for public comment.

Back-door manipulation of property valuations by lawmakers or unions to spare the Council a politically uncomfortable vote to increase the tax rate would be a gross breach of public trust — and possibly a violation of the law.

Mayor Rick Blangiardi had a different view from Say’s, telling the Star-Advertiser’s “Spotlight Hawaii” livestream program that soaring property assessments — averaging 12.4% islandwide and exceeding 20% in some areas — were “a real aberration” that “caught us completely by surprise.”

He pledged to give homeowners relief “that’s material, that’s significant” to “peel back” any undue revenue windfall to the city.

Blangiardi wasn’t specific, but his aides have spoken mostly of one-time credits and exemptions that would leave the aberrational high valuations baked in as the base for future assessments.

It creates a vicious cycle in which unduly high valuations cause arbitrators to give city workers bigger pay raises, creating a need for high future valuations to sustain raises.

The mayor ruled out the more direct approach of balancing the aberrational valuations by lowering the tax rate, arguing that Honolulu’s property tax rate is among the lowest in the country.

True, but also somewhat misleading. Mainland rates are higher because public schools are a local function funded by property taxes.

Hawaii has the nation’s only statewide school system, funded by the state’s excise and income taxes. Our overall tax burden, combining the state and county taxes, is among the nation’s highest.

The key point is most agree this year’s valuations are an aberration that will unfairly strain Oahu homeowners.

What’s needed is relief that permanently corrects the aberration, as well as a prompt independent investigation — by enforcers of the law, if warranted — to identify the cause of this suspicious anomaly.

Reach David Shapiro at volcanicash@gmail.com.