Infrastructural deficiencies are leading an increasing number of industries into alternative solutions to the traditional public monopoly, including total own production. Anas and Lee suggested six behavioural types of marginal privatisation-i.e. the introduction of industrial producers as suppliers of urban services for themselves or for a limited number of nearby industries—emphasising its positive impact on the profitability of industrial production. This paper first suggests an extension of Anas and Lee's typology and the impact of marginal privatisation is then discussed in terms of the financial equilibrium of the public organisations responsible for the residual services to domestic users, and with respect to environmental objectives. Finally, suggestions are made for water and sanitation services in Casablanca based upon a mixture of behavioural types primarily designed according to the environmental risk associated with each industry group.