ICH Q7 - Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients 4.3: Show process water is fit for use (at least drinking-water quality unless justified), set tighter specifications where needed and validate any in-house treatment

What does 4.3 require?

Water used to make APIs should be shown to suit its use. Unless otherwise justified, process water should meet at least the WHO drinking water guidelines. Where potable water cannot assure API quality, tighter physical and chemical, total microbial count, objectionable organism or endotoxin specifications should be set. Where the manufacturer treats water to a defined quality, the treatment should be validated and monitored against action limits. If a non-sterile API is meant or claimed to be suitable for making sterile medicines, the water used in its last isolation and purification steps needs monitoring and control of total counts, objectionable organisms and endotoxins.