Greywater generally involves cleaning products such as soaps. Your toilet bowl cleaner could probably take the paint off your walls. If you need to wear gloves

Greywater generally involves cleaning products such as soaps. Your toilet bowl cleaner could probably take the paint off your walls. If you need to wear gloves to use a cleaning product your greywater is questionable. Unless there is some processing step your "greywater" is likely toxic. This isn't the 17th century. "Better Living Through Chemistry" -- Dupont ad