Epoxy grout does not absorb water. That is the whole point of it. Cement grout is porous, so it soaks up water, holds soap residue and eventually grows mould in the joint no matter how often it is scrubbed.

Does not absorb water or stain the way cement grout does
Far better resistance to mould in shower joints
Holds its colour instead of going patchy
Well suited to commercial and food areas
We will tell you when you do not need it

Epoxy is a two part product that goes off quickly once mixed, so it has to be worked in sections and cleaned off the tile face before it cures. That is why it costs more to install than standard cement grout.

In return you get a joint that does not absorb water, does not stain from soap or shampoo, and does not go patchy as it ages. In a shower used every day, that difference shows within a couple of years.

It is not always the right call. On a dry hallway floor or a feature wall, cement grout is perfectly adequate and we will tell you so.