Judgment unanimously reversed on the law with costs and new trial granted. Memorandum: Petitioner appeals from a judgment dismissing its petition brought pursuant to article 7 of the Real Property Tax Law to review the tax assessments on its property in the Village of Brocton, Town of Portland. The Hearing Officer dismissed the petition at the close of testimony of petitioner's appraisal expert on the ground that petitioner had failed to overcome the presumption of validity of the assessment. That was error.

Tax assessments are presumptively deemed valid (Farash v Smith, 59 N.Y.2d 952, 955), and a petitioner challenging its assessment has the ultimate burden of establishing that the property was overvalued (Matter of Barnum v Srogi, 54 N.Y.2d 896, 899). It is, however, well established that the presumptive validity of an assessment disappears when a petitioner presents substantial evidence that the assessment was excessive (People ex rel. Wallington Apts. v Miller, 288 N.Y. 31, rearg denied 288 N.Y. 672; Matter of Carriage House Motor Inn v City of Watertown, 136 A.D.2d 895, affd 72 N.Y.2d 990; Matter of Adirondack Mtn. Reserve v Board of Assessors, 99 A.D.2d 600, affd 64 N.Y.2d 727).

Here, petitioner presented substantial evidence that the assessment was excessive. For the tax years 1981 through 1985, respondents valued the property at over $500,000. In 1982, petitioner was advised by the Chautauqua County Industrial Development Agency not to ask more than $250,000 for the property. Petitioner was unable to find a buyer for the property at that price and lowered the asking price over the next several years until the property was sold in 1985 at public auction for $27,000. An arm's length sale of the property is strong proof of the fair market value of the property sold (Matter of General Elec. Co. v Town of Salina, 69 N.Y.2d 730; Grant Co. v Srogi, 52 N.Y.2d 496).

Respondents contend that the appraisal proof is inadequate as a matter of law to sustain petitioner's burden of overcoming the presumption of validity of the assessment. While we agree that the appraisal report contains numerous errors and deficiencies, it substantially comports with the uniform rules (see, 22 NYCRR 202.59 [g] [2]). In any event, the nonappraisal evidence was sufficient to sustain petitioner's burden.