Principle of affordability is used for assessing the highest possible tariff rate that a family with median household income can monthly pay from its income for the average consumption per person, and where other main financial obligations (e.g. for education or health) would not be threatened.

In practice, this ceiling is usually set at 4% of the median household income for the water and sewerage bill, but a separate approach can be developed for each type of service, particularly since considerably higher costs are expected in the sewerage sector in the coming period, when facilities for wastewater treatment will be constructed.

There will always be a certain number of persons /households in local community who cannot afford to pay their water bill.  Those persons, which have to be registered as socially vulnerable categories, should be assisted in some other way through subsidies, vouchers or otherwise, and not by reducing the water tariff rate for all consumers.

Such an approach will ensure realising the human right to water as recognized by the UN Convention (On 28th July 2008, through Resolution 64/292, the United Nations General.