Bacterial growth in drinking water supplies is a concern for public health, aesthetic aspects, and system operations. Therefore, it is essential for drinking water utilities to control bacterial growth during distribution by ensuring high water quality. Reverse osmosis (RO) is a promising technology to produce such high quality water due to its effectiveness in removing bacterial loads and growth-supporting nutrients. Measuring the bacterial growth potential (BGP) of water reliably is important to understand and manage drinking water distribution networks. This is especially crucial for pure drinking water with ultra-low nutrient content such as remineralised RO permeate, where the existing methods cannot be applied. Hence, the existing BGP method was developed during this study to obtain reliable results for remineralised RO permeate. The developments aspects included the detection limit of the method (blank), the effect of sample handling procedures on the final outcome, and the way of expressing the results.