Where are water chestnuts grown?

Water chestnuts are notoriously difficult to grow here in the UK; just for ornamental ponds. But the Chinese produce them by bucketloads. Is there a climatic factor and are they farmed or just harvested in the wild, and either way how safe are they to eat given the risk of water pollution in China's rapidly expanding economy?

Where are water chestnuts grown?
WATER CHESTNUTS ARE GROWN WITH GREAT CARE....IOWA HAS A GREAT CLIMATE AND GROWING CAPABILITIS FOR WATER CHESTNUTS....THEIR GROWTH IS DEPENDANT ON MANY FACTORS WIND AND WATER CAN AFFECT THEM TREMENDOUSLEY
Reply:south east asia
Reply:in the water...