Does everybody’s tax go up because of revaluations?

No. Revaluation redistributes the existing property tax burden so that all property owners pay their fair share based on the market value of their property. If the total tax levy remains the same, only those properties, which are not presently paying their fair share of the tax burden, will pay more tax because of the revaluation. Property owners currently paying more than their fair share would actually pay less after the revaluation.  The total amount of taxes levied is completely independent of the overall assessment.