> Yes so like it would leak downstairs.

For it to show up downstairs, there must be a fair amount of water that is not making it into the shower pan.

If you have pools of water on the bathroom floor after you shower, the problem is not with the tiles and grout, but with your not containing the water properly in the first place. If this is the case, the simple solution is to determine the path of the water from the shower area to the floor and block off that path so that no water can escape the shower area.

If there are no signs of water on the flooring itself, then your next check is to make sure that the border between the walls and the shower pan is caulked properly.

Unless there are major portions of grout missing, this should not be an issue.

As others have suggested, if there isn't any visible pooling, it is probably a leak in the plumbling,