Water and wastewater treatment through the use of membrane filtration technology is one of the processes utilised currently to meet the growing demand for water. While new technologies can harness water from various non-traditional sources such as oceans, there remains the possibility of making drinking water more expensive through the use of costly treatment equipment. To prevent this and ensuing catastrophes around the world, the water industry needs a strategy that keeps the price of water and price of products aiding in the treatment of water controlled into the future. The overall aim of this study is to develop an analytical index that could be used by the water industry to measure, monitor, and control the price of water. A structured method to evaluate membrane manufacturing costs against the lifetime performance of membranes was developed. The method was then extended and a costing model for the application of membrane in water and wastewater treatment plants was established. Thereafter, a software application was developed to aid in the implementation of the analytical index. The results indicate that, with a measurable index in place, the evaluation of technologies with respect to the cost of water production can be effectively carried out.