The dormitory building of the school adopts non-negative pressure equipment for water supply. Should a backflow preventer be installed at the water inlet of the pump? There is a check valve on the out

The dormitory building of the school adopts non-negative pressure equipment for water supply. Should a backflow preventer be installed at the water inlet of the pump? There is a check valve on the outlet pipe. Non-negative pressure water supply equipment is not equipped with backflow preventer at the water inlet of the pump, but in principle it is required to collect backflow preventer at the water inlet of the equipment, mainly depending on the region. For cities with strict municipal management (such as Beijing), it is necessary to install backflow preventer at the water inlet of the equipment, otherwise it will not pass the acceptance, but other areas can coordinate, mainly depending on the requirements of Party A and the water supply company. No matter what kind of water supply equipment, the pump outlet must be equipped with a check valve.