N.J. Stat. Ann. § 2A:18-61.61

2. Whenever a tenants' organization agrees to accept billing for a utility service, the tenants comprising the membership of the organization accepting and paying such billing shall be permitted to deduct from each of their respective rental payments to the landlord of the premises an amount corresponding to the tenant's contribution towards the currently due utility payment and the arrearage, if any, owed by the landlord, provided that any contribution by a tenant to the arrearage shall not exceed 15 percent of the tenant's rental payment which would have been payable to the landlord, but for the contribution.