Has anyone experienced green water because of improper grounding of appliances? Or whole house?

[CanOfWorms]

Has anyone experienced green water because of improper grounding of appliances? Or whole house?

I have a client/landlord and their tenant is complaining of green water.
It looks like copper.

I know copper pipes corrode green inside, but usually this coating is stable.

He installed an electric tankless water heater himself along with the dishwasher and the fridge water.

I read that improperly grounded appliances connected to the plumbing can cause excess corrosion through electrolysis.
Any thoughts on this?

 

[DonL]

May be algae. Look at it under a microscope.