non-revenue water. it is broken down into 21% physical losses and 13% commercial losses from undermetering, illegal connections and authorized unbilled consumption such as for mosques. in addition, 24% of billed consumption is not being paid. the overall level is high by international standards. a recent benchmarking study showed that the regional directorates are employing 10,500 people to serve 5.7 million customers. this corresponds to about 10 staff per 1,000 connections, which is more than three times higher than in the case of efficiently run utilities. the actual number of people employed in service provision is even higher because many directorates contract out specific services. tariffs and cost recovery tariffs. the kingdom has a single increasing block tariff structure for the entire country. under that structure water and sewer tariffs per unit of water increase with consumption. the new residential tariff schedule - in force since january 1, 2016 and shown in usd equivalents at the exchange rate of january 2016 - is as follows: household usage (m3/month)water tariff ($/m3)sewage tariff ($/m3)combined tariff ($/m3) 0-150.030.010.04 16-300.270.140.41 31-450.810.411.22 46-601.080.541.62 61+1.620.812.43 under the new tariff schedule the limit for the first consumption block now is 15 cubic meters per month, down from 50 cubic meters per month previously. the tariff is the first block remains extremely low, but it subsequently increases significantly. the new tariff schedule also introduces a sewer tariff which did not exist before in saudi arabia. tariff adjustments had been proposed for at least six years, but had never been implemented. the increase came following a significant drop in oil prices. the ministry of water says that the majority of households would not be significantly affected by the increase, because their consumption remains within the lower consumption blocks. commercial, industrial and government users are charged according to different, higher tariff schedules. prices for water sold by tanker trucks. a cubic meter of water supplied by a water tanker may cost as much as 6 riyals (us$1.50), or about 20 times more than water supplied through the network. citizens who are not connected to the piped network, who are often poor, pay up to 40 times more for water than connected households. the monthly water bill is about 1 riyal (us$0.27), compared to an average mobile phone bill of 200 riyals. the price of a 19 cubic meter tank is 150 sr, and the price of a 30 cubic meter tank is 180 sr. although price may change during holidays and peak seasons, and not all cities are the same. sale of treated effluent. through the treated sewage effluent initiative (tsei) of the national water company, treated wastewater is sold to major water customers, such as industries or golf course operators, under long-term contracts of up to 25 years. this generates a revenue stream that recovers the costs of wastewater treatment under build-operate transfer (bot) projects financed by the private sector. as of 2011, it was estimated that nwc had signed tse agreements worth more than 5 billion saudi riyals (usd 1.33 billion). cost recovery and subsidies. before the 2016 tariff increase, on average "the government (was) only recovering one or two percent of its costs, and the (subsidy) plans are benefiting the rich, not the poor", according to adil bushnak. according to a 2000 estimate by the world bank, the government paid annual subsidies of us$3.2 billion, equivalent to 1.7% of gdp and 7% of oil revenues. desalinated water is provided for free by swcc to nwc. before the introduction of the private sector in riyadh, the riyadh branch of mowe – probably one of the best performing branches - had revenues of 370 million riyals in 2004, but expenses of 570 million riyals. investment and financing all investment for water and sanitation, including desalination, is funded directly by the central government's budget. the 7th and 8th development plans (covering the periods 2000-2005 and 2006-2010 respectively) allocations for water (including irrigation), covering a period of ten years, amounted to saudi riyal 34.9 billion (us$9.2 billion) and saudi riyal 41.6 billion (us$11.1 billion) respectively, equivalent to us$2 billion per year. it has been estimated that between 1975 and 2000 a total of more than us$100bn has been invested in water supply and sanitation, and that a further us$130bn will be needed between 2002 and 2022, corresponding to us$6.5 billion per year or more than us$200 per capita and year. this level of investment in water per capita is among the highest in the world, higher than in the us, the uk or germany, due to the high cost of desalination and the need to transport water over long distances. it corresponds to about 1.5% of gdp.