the lowest consumption block. The introduction of water tariffs for residents aims at reducing subsidies, encourage the efficient use of water and raise awareness of the importance of reducing consumption. It was combined with a large public relations campaign, as well as advice for customers who want to save water. Even before the change in tariff, bills highlighted water usage beyond a certain level in red and showed the subsidy paid by the state. The two public distribution companies receive a government subsidy. In turn, they pay a bulk supply tariff reflecting the full economic cost to ADWEC, which in turn pays for the water received from the private IWPPs under Water and Power Purchase Agreements. Bulk supply tariffs are adjusted by the RSB every four years based on maximum allowable revenues. Investment and financing Investment in desalination plants is financed by the private sector through BOO contracts. Investment in water distribution and sewerage infrastructure is financed by the government through subsidies to the respective public companies. Investment in both power and water production and distribution was more than US$36 billion from 1999 to 2008. Since power and water are produced and distributed by the same companies, separate figures for investment in water infrastructure are not available. See also Sanitation in Dubai References External links Regulation and Supervision Bureau for the Water and Electricity Sector in the Emirate of Abu Dhabi Environment Agency Abu Dhabi Abu Dhabi Economy of the Emirate of Abu Dhabi