On a good day in Lagos, the city’s water company supplies enough water for just seven million of the city’s 20 million residents.That is where the water vendors come in – to fill a void and supply the rest of the city’s population. However, many residents are unhappy with the high cost of water they say the government should be providing.City water officials say the system is long overdue for an upgrade, but that the high cost cannot be afforded by the government alone.Al Jazeera’s Mohammed Adow reports from Lagos.