Water pollution has long been a crisis of life-threatening proportion in many Muslim countries. It is therefore timely to determine the role of traditional Islamic jurisprudence in outlining the water quality standards. This study examines the Islamic and scientific approaches in appraising water quality. More specifically, this study used the Taharah–Najasah (T–N) standards (pertaining to purification and degree of pollution) as stated in Islamic jurisprudence of purification to analyse the water classes, index ranges and parameters of the water quality index stipulated by the Malaysian Department of Environment. It is important that the T–N standards are taken into consideration in determining the water quality so that Muslim communities are assured of the purity of the water used in performing worship and instilling healthier water habits among Muslims. At the same time, the application of T–N standards in gauging water quality will also benefit the whole nation as the unique characteristic of mutlaq water (purest and purifiable water) can help significantly in formulating an innovative and advanced water quality index and hence in alleviating the water pollution issue The resemblances can be found in the aspects of acceptability (taste, odour and appearance).