The companies, which are listed on the Athens stock exchange, post profits despite low tariffs, partly due to investment subsidies from the state.

On average, Greece has quite abundant water resources of 58 billion cubic metres per year (1977–2001), of which the country uses only 12 percent.

Water resources are especially scarce on the Greek islands, some of which are supplied by tanker ships or have turned to seawater desalination.

However, some smaller islands have insufficient water resources and have to be supplied via tanker ships at a high cost.

For example, the islands Kimolos, Irakleia, Schoinoussa, Symi, Halki, Patmos and Kastelorizo (Megisti) were partly or entirely supplied via tankers as of 2008.

A small wind-powered floating desalination plant has been built as a pilot in 2008 and has been anchored off the shore of Irakleia.

The Hellenic Union of Municipal Enterprises of Water Supply and Sewerage (EDEYA), founded in 1989, represents 155 DEYAs.

The so-called Kallikratis plan approved in May 2010 foresees the redrawing of the boundaries of Greek municipalities and giving them more resources and responsibilities.

Many of the municipal utilities created at that time were small and have faced financial difficulties due to low tariffs and excessive hiring[citation needed].

A Greek Ministry of Finance document of 2010 discusses the possibility of creating a holding company to be called Hellenic Waters S.A. for the entire country including EYATH, EYDAP and the DEYAs.

In June 2010 the Ministry of Finance announced it would reduce its share in the two companies to 51% as part of a broader Hellenic Privatisation Programme.

Its name derives from €136, which is the estimated value of EYATH's shares that were to be sold originally – 50 million Euro – divided by the number of its water customers.

[11] Kostas Marioglou, a union leader and activist of initiative 136, insists that the initiative does not want to preserve the status quo of a "state company where the management is political appointments with no water service experience, running the company poorly before they move on to another party position.

Diane D’Arras, Vice-President of Suez, promised annual investments of between 25 and 50 million Euro as well as the creation of 4,000 jobs through privatisation .

Also, cash revenues may decline due to difficulties in collecting bills from customers whose incomes have been reduced through public sector wage cuts.

[13] According to one report, EYATH allegedly "supplies the cheapest water in Europe", while actually its tariffs are higher than e.g. in Rome and among the highest in Greece.

Iraklion on the island of Crete and Patras are situated in areas not declared sensitive and provide full secondary treatment followed by nitrogen removal.

In 1999, Greece had identified under the mechanism provided by the Directive 34 lakes, rivers, estuaries and coastal water bodies as sensitive areas due to eutrophication.

According to the European Commission, in 2002 (no more recent information from the EC is available) the towns of Elefsina Aspropyrgos, Grevena, Kilkis and Theva discharged their wastewater in sensitive areas without any treatment.