Is grout waterproof?

Is grout waterproof?
Contrary to popular belief, ceramic tile and grout, by themselves are not waterproof. Water can penetrate through cement-based grout and work its way through the substrate. To prevent water damage, you must install a waterproof membrane just below the tile bonding mortar as close to the tile as possible.

Reference:
Waterproof a Tiled Shower the Right Way | Custom
Jul 11, 2016

Is grout waterproof?,frequently asked question,question and answer,answer,