On 12 and 13 June 2011, 27 million Italians voted in a national abrogative referendum, the only type of referendum allowed by the Italian Constitution. They represented around 57% of the electorate, significantly beyond the 50% plus 1 threshold required by Italian law for its results to be valid. This threshold had not been reached in any of the 24 referendums held in the country since 1997. Of the four questions on the ballot, two of them addressed privatisation of water. The first question concerned the obligation of public authorities to select the providers of water services by way of bids open to public, private and mixed companies; the second, the inclusion in the water tariff of a quota (fixed by law at 7%) for the remuneration of the capital invested by the company managing the provision of water. The remaining two questions addressed the abrogation of a plan to restart the production of nuclear energy and the so-called ‘legitimate impediment’, which enabled cabinet ministers to avoid criminal prosecution while serving in their posts. The citizens who voted Yes (that is, for abrogation) were 95.4% on the question about the private management of water provision; 95.8% against the fixed remuneration for private investors in water supply; 94% on nuclear energy and on the ‘legitimate impediment’. In the referendum, as many as 25 million Italians voted against the government's position (Chiaramonte and D’Alimonte, 2012).

In order to have a national abrogative referendum called, a coalition of social movements had obtained the support of 1.4 million signatories, almost three times the number required by the Italian law to initiate a citizen-induced referendum. The collection of the signatures has been presented as ‘an incredible sign of vitality of the commons movement, which mobilized tens of thousands of volunteers, collecting nationwide signatures in the most remote corners of the country. People usually skeptical of political collections of signatures actually lined up, sometimes for hours, to sign’ (Bailey and Mattei, 2013). The signatories were subsequently certified one-by-one by a notary or other public official. Admitting the two questions on water issues, the Constitutional Court rejected the claim by the referendum's opponents that the liberalisation of local public services was required by European Union (EU) law.