inter-municipal utilities (Zweckverbände); 63 percent are utilities under private or mixed law either under private, public or mixed ownership.; and 6 percent are water and land associations (Wasser- und Bodenverbände). Only 3.5 percent of service providers were entirely privately owned (no figures are available on companies with mixed ownership, an increasingly prevalent form of ownership). Sanitation Unlike public water supply, sanitation is considered a sovereign core responsibility (hoheitliche Kernaufgabe) of municipalities in Germany. This implies that, unlike water supply, it is exempt from VAT and corporate taxes. It also implies that companies under private law cannot directly provide sanitation services. The great majority of municipalities thus provide sanitation directly through a municipal sanitation department (Regiebetrieb). Less than 10 percent of the 6,000 sanitation providers are utilities under public law, and none are utilities under private law. However, municipalities or municipal utilities can sign operating contracts (Betreiberverträge) with private companies. Out of the 900 largest sanitation service providers, about 10 percent have signed such contracts for sewerage services and 12 percent for wastewater treatment services. Examples of large water and sanitation service providers The largest privately owned public water company is Gelsenwasser AG, although 92,9% of it are still owned by various municipalities, which is a multi-utility company (water, sanitation and natural gas distribution) serving 3.2 million inhabitants in North Rhine-Westphalia, under concession agreements with 39 municipalities, and many other localities throughout Germany and internationally. An example of a publicly owned large multi-utility (water, electricity generation and distribution, natural gas distribution) is the Mainova AG in Frankfurt. The Berliner Wasserbetriebe, an Institution under Public Law (Anstalt des öffentlichen Rechts), is the largest communal water service provider after its remunicipalisation in 2013, serving 3.5 million people with water and 3.9 million people with sanitation services. Policy and regulation Responsibility for policy setting in public water supply and sanitation in Germany is shared between the EU, the federal government and state governments (Länder). (For more details on the role of the Länder and municipalities see States of Germany) The EU sets the framework legislation for water quality and water resources management (see EU water policy). The organization of public water supply and sanitation, however, remains a prerogative of EU member states. The German states (Länder) play a key role in the sector by setting, among other things, the legal framework for tariff approvals. Municipalities, legally entrusted with service provision, play an indirect role