I have lived in a co-op for the past three years. I am planning on having my boyfriend move in with me in a few months. Are there any rules or regulations that will prevent that from happening within my co-op?

—Subleasing Shareholder

A “Each cooperative housing company has a standard lease with its shareholders. This lease, usually called a proprietary lease, covers all sorts of topics,” says Andrew P. Brucker, Esq. of the law firm of Schechter & Brucker, P.C. in Manhattan. “It sets forth, among other things, who is responsible for repairs, what various events would constitute a default, what rights the shareholder has to sublease his unit, and what rights the shareholder has to transfer his unit. The proprietary lease also states who can live in the unit.

“Quite often, the proprietary lease provides that the unit may be occupied by the shareholder and members of his immediate family, though some leases go further. Often there is a definition of ‘immediate family’ but not always. For example, some leases include in ‘immediately family’ domestic partners. And so the cooperative corporation’s right to control the use of the co-op apartment (and by whom) has always been thought of as an essential right of the corporation.

“However in 1983 New York State passed the ‘roommate law’ which is found in the Real Property Law Section 235-f. The law provides that any landlord’s attempt to limit the occupancy of any residential rental property, by lease or otherwise, to the tenant and his immediate family is against public policy. It then goes on to state that any lease entered into by a tenant shall be construed to permit occupancy by the tenant, his immediate family, one additional occupant, and dependent children of the occupant. This law applies only if the tenant is using the apartment as a primary resident.

“Though it might seem, upon first reading, that the law applied only to rental apartments, the courts (as early as 1988) have held that the roommate law applied to cooperatives.

“Therefore, assuming that the letterwriter is using the cooperative apartment as a primary residence for herself, and she wishes to have her boyfriend live with her, the law would allow the arrangement. And the cooperative housing company would have no right to bar him, regardless of what the lease states, and regardless what the board policy might be.”