## Facts

- Pauline Hellerstein owned real property on Fire Island in the Town of Islip, New York.
- Islip’s assessment roll used fractional assessments, concededly valuing property at a percentage of market value.
- Hellerstein filed an Article 7 Real Property Tax Law (RPTL) proceeding alleging the assessment roll was illegal because it violated RPTL § 306, which requires assessment at “full value.”
- She did not claim her own parcel was overvalued or assessed unequally; she challenged the legality of the assessment method used for the roll generally.
- The Supreme Court, Suffolk County dismissed the petition; the Appellate Division affirmed without opinion.
- The New York Court of Appeals granted leave to appeal.

## Issues

1. Whether RPTL § 306’s requirement that property be assessed at “full value” forbids a systematic practice of fractional assessments based on a percentage of market value.
2. Whether, in an Article 7 proceeding alleging illegality, a taxpayer may obtain relief directed at the assessment roll and, if so, what remedy is appropriate where immediate invalidation could disrupt local finances.

## Decision

- The Court of Appeals held that “full value” in RPTL § 306 means full (market) value and that systematic fractional assessments violate the statute.
- The Court rejected reliance on long-standing administrative practice and claimed administrative difficulty as a justification for ignoring the statutory mandate.
- The Court declined to declare the existing assessment roll void, instead ordering prospective compliance to allow an orderly transition and avoid fiscal disruption.
- The judgment dismissing the petition was modified to recognize the illegality and direct future conformity with the statute.

## Legal Principles

- RPTL § 306 requires assessment at full value, construed as fair market value when market value is ascertainable.
- A consistent administrative practice contrary to clear statutory language does not change the statute’s meaning or excuse noncompliance.
- Under RPTL Article 7, a taxpayer may challenge the legality of an assessment method, not only parcel-specific overvaluation or inequality.
- Courts may tailor remedies for systemic tax illegality to prevent immediate disruption, including prospective relief requiring future compliance.

## Conclusion

The court held that Islip’s fractional assessment system violated RPTL § 306’s full-value requirement, but it fashioned prospective relief—directing future full-value assessments—rather than invalidating the existing roll.


Hellerstein v. Assessor of Town of Islip, 37 N.Y.2d 1, 332 N.E.2d 279 (N.Y. 1975)