Particularly in smaller buildings, landlords are sometimes delinquent in paying utility bills for oil, gas, electricity, or water. By law, utility companies must notify the tenants in buildings before shutting off service. Tenants then have the opportunity to make payments themselves for the services, and can deduct these charges from the rent. If you're facing this situation in your building, it's an opportunity to organize a Tenants' Association, and band together to protect your rights. Then hire a Tenants' lawyer who has experience representing tenants collectively and knows how and when to negotiate, or to implement a rent strike.
Attention New York City Tenants: Get information on bad conditions in your apartment at the McAdams Law main site here.