Two approaches by Private Sector Involvement (PSI) in drinking water supply are followed in Ghana. In the urban areas the public utility (Ghana Water Company Limited) now has private sector management via a management contract, whereas in the small towns and rural areas the responsibility for water services is decentralised. The District Assemblies use the Community Water and Sanitation Agency and local expertise in the private sector. These are examples of PSI where the private sector participates without investment risks. The paper compares the two approaches and draws out lessons for improving the design of PSI arrangement.