QUESTIONMy bathroom marble floor has been grouted twice now and has not hardened. I have a water softener. Would that make a difference?
ANSWERANSWER - If you are using a cementitious grout it should harden. If you used too much water in mixing the grout and/or too much water in cleaning the grout during the installation of the grout you can weaken the grout causing it not to harden.
In some cases if the grout dried too fast it may not have been able to fully hydrate, so if you wet the grout again it can then continue to harden.
I have never heard of water softener water affecting grouting.