Why Does Black Grout Turned Grey

If too much water is used during the wiping up and cleaning up phase of grouting, the extra water will dilute the concrete-to-colored-pigment ratio. Once the grout begins to dry, it will have more concrete than color, which means gray will be the prominent color.

Does black grout go GREY?

Does black grout fade? Yes, unfortunately, black grout fades over time. Grout, regardless of color, is extremely porous and essentially takes on anything that it comes in contact with–unless it is properly sealed.

How do you clean black grout that has turned white?

A solution of half water and half vinegar is also effective at cleaning both dark grout and white floor grout. Fill a spray bottle with the solution and apply directly to the grout. Give it a few seconds to penetrate the dirt and wipe clean with a damp cloth. Repeat as necessary.