The need for a colorimeter with low capital and maintenance costs has been suggested for investigating water pollution in developing countries. This paper puts forward a design of such a device based on materials which can be purchased locally at very low cost (or salvaged electronic parts). It is shown that proper selection of the components will allow the cost objectives to be met and also provide acceptable precision and accuracy. The colorimeters in this study were designed to use inexpensive electronic components, such as light emitting diodes and photoresistors, which are readily available and hence render them affordable in many applications. The aim of this paper is to present a low-cost design of a colorimeter with regard to the maximum achievable accuracy and versatility in application. After testing the prototype instruments, it was found that Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma (ICP), Digital Water Analyser (DWA) using pack test and the Low-cost Colorimeters (LCCs) yielded identical results. It can be said that Manganese (Mn) in a mine effluent water sample was determined successfully using the LCC and hence can be applied to measure water related pollution parameters, on condition that a stable colour can be generated with an appropriate reagent, and hence a versatile tool for investigating the state of the environment.