If you are asking that question, your only option is to pack up and slip out into the night. Just kidding. But you should ask that question when you move into the apartment, not when something goes catastrophically wrong. The key word is вентиль, which means a turn-off valve. When you move in, ask about them or look for them in the kitchen, toilet and bathroom. There are also usually two valves that control the hot and cold water when they enter the apartment. Find them, test them, oil them and mark them. While you’re crawling around, you should also figure out how to turn off and on the water to all the radiators. And you ought to know where the main turn-off valve is to the gas, if you have it in the kitchen. By law, that valve has to be accessible, and once a year the gas man will come around to check it. The other thing you should get from your landlord is the number of the dispatcher (диспетчерская служба) that handles disasters for your house.