Lagur produces a chemical-free treatment method for lime-scale treatment of drinking water pipes, heating and cooling systems. Anecdotal evidence has suggested that that their treatment system also gives an improvement in microbial water quality, and so Lagur would like to provide a measure of microbial water quality to its customers. Typical microbial water quality tests are expensive, and time-consuming, and the result often is not available until a number of days after taking a water sample. This project links Lagur (an SME) with researchers from DTU Aqua and DTU Miljø, to investigate together the potential for developing an optical method of monitoring microbial water quality, that could be used in an online manner at sites which utilize Lagur's chemical-free treatment systems.