Scale and scope economies in the water industry determine the most cost-efficient way to organize water and sewerage services. Evidence shows that combining water production and distribution is beneficial, but the benefits of combining water and sewerage activities are less clear. Companies can save money by reaching a certain size, but costs increase if they grow too large. The optimal size of utilities varies between countries. These findings have implications for water pricing and suggest the need for more research on these economies and why they differ between countries.