There is, however, no sewerage tariff harmonization for the locations serviced by ONEP, in contrast to tariffs for drinking water consumption (table 4.3). A tariff analysis of 42 wastewater treatment systems operated by ONEP around 2006 showed that the sanitation tariffs allowed recovery of only about 70 per cent of the operating costs, excluding depreciation allowances, financing costs and costs of maintenance of the infrastructure. In other words, given the general increase in major cost items for wastewater management, there has been an increasing gap between the actual tariffs and the level required for ensuring recovery of operating costs, let alone maintenance and depreciation.