I would like to import water faucets. What kinds of restrictions are there on their materials?  

Water supply equipment such as faucets should conform to technical standards concerning structure and materials prescribed by cabinet order.

1. Each municipal waterworks bureau (the water supplier) may stop the water supply if the structure and materials of water service installation do not conform to standards prescribed by cabinet order. Consequently, domestic water supply equipment should conform to the "technical standards concerning structure and materials of water service installation " (Hydrostatic Pressure Resistance, Water Quality Effect, Water Hammer Prevention, Backflow Prevention, Back-siphonage Prevention, Durability, Freezing Temperature Resistance) prescribed by the Enforcement Order of the Waterworks Law.

2. In the case of certifying faucets, a self-certification and third party certification system is in place, and third-party certification is being implemented by several testing organizations including foreign agencies, as well as the Japan Water Works Association.