Unlike other towering New York City structures, the Empire State Building's water tanks are located within the structure rather than on the roof. Seventy miles of pipe supply water to the whole structure as well as the fire-protection standpipe system. The building's owners, who rent out space to businesses, also have the right to purchase water from nearby sources. The building's early managers decided not to install pipes inside the walls for fear that it would be too expensive. They did, however, include a small standpipe in each room with a sink or toilet. These were intended to provide emergency drinking water in case of fire or vandalism. In fact, they have occasionally been used as such during major fires at other buildings near by. Today, the building's owners can choose to have their floors piped for permanent installation of water heaters or they can go without, but it is recommended that they be installed if possible because heat from people's baths and kitchens can lead to mold growth inside the walls. In case of severe drought, the building's owners can request that city officials allow them to draw water directly from one of the city's aquifers. This procedure is called "conservation pumping". The first two water tanks arrived at the building site in 1934.