Countries introduce private sector participation into the water and wastewater utilities sector for a number of reasons. The introduction of a profit motive may increase efficiency as compared to public management of the water system, and private firms have been noted for customer service improvements. Financial considerations, including revenues from the sale of assets and reductions in the direct cost of providing water services, may also motivate governments to introduce private sector participation in this industry. However, because water is a basic human necessity, the introduction of private participation in this industry sector may raise social, economic, and national security concerns. Private participation in the global water and wastewater industry can take a number of forms- including privatization, greenfield projects, concessions, leases, operation and management contracts, and outsourcing- and most countries employ a mix of methods. A handful of European firms dominate trade and investment in the global water and wastewater utilities market.