I doubt if washing up water will help with this as there will be plenty of dry places amongst the roots for the ants to shelter. I believe that there is an ant killing powder available in garden centers, otherwise you will need to remove the azalea from the pot, wash all the compost from its roots and repot in fresh compost.
The presence of ants (if, indeed, they are ants) in the first place indicates that the compost in the pot has been on the dry side.