Kenyan government through NEMA has been advocating and pressurizing business entities in taking up the responsibilities of conserving its environment. The study intended to identify the effect of green water management undertaken by manufacturing companies on their performance. The study was conducted in Thika municipality where different manufacturing companies operate and samples of 31 respondents were considered valid. The study adopted descriptive research, taking both qualitative and quantitative approach utilizing both secondary and primary data. The population included those companies that practice environment management where purposive sampling technique was used and a sample of three companies were selected. The main respondents of the study were the top and middle level managers and operational staff in the production department. Data was collected using structured questionnaires combined with personal interviews and observation which were then sorted and coded. The data was analyzed using descriptive statistics. SPSS aided in data analysis. The major effect of green water management was found to be on finances where 77.4% said the initial cost of water plant, equipment and technology as well as maintaining the practices was high. The high initial cost forced some companies to forego the practices. Adopting water conservation and management affected the performance of the company in that the company’s social relation with neighborhood is good thus having peaceful coexistence while doing its businesses. In addition by managing water, the company’s competitiveness increases due to government endorsement through certification