Abstract: Dye-house water quality is the most important parameter to be confirmed before dyeing; precisely the presence of metal content i.e. Hardness. This research will investigate & analyses the impact of separate hardness (i.e. Calcium, Magnesium & Iron) on particular ‘Turquoise’ (C.I. Reactive Blue 21) & a ‘High Exhaustion’ class (C.I. HE Red 120, C.I. HE Yellow 84) of Reactive dye on cotton knitted-fabric. From evaluation of dyed fabric the range of metal content is sorted out where the quality starts to fluctuate as distinctive visible & spectral change of shade & fixation rate of the dye molecules has been found. The result of the work will help for further projection about water quality degradation in upcoming years & its effect on dyeing behavior, also the sustainability of present dyeing process to cope with the ever degrading quality of water.