While the terror campaign claimed more than 4,000 lives, the shortage of potable water and poor sanitation led to about 73,000 deaths, according to WaterAid, a London-based non-profit.
The water deficit isn't limited to isolated areas in the country's vast north. In Lagos, about 15 million of the coastal metropolis' 21 million have limited access to piped water.
Africa's accelerating urbanisation is colliding with governments' failure to provide the most basic services. Next year alone, Lagos will add more than the population of Boston, worsening its infrastructure shortfall.
"Water is strained, transportation is strained, housing is strained," Toyin Ayinde, the state commissioner for planning and urban development, said in an interview.
People still need about 25 gallons a day, the state-run Lagos Water Corporation reckons.
That's where Mohamed Adamu comes in. Starting at 5 a.m. every day, he fills 10 jerry cans and walks down rutted streets to deliver clean water to corrugated iron-roofed homes in the Otumara district about a half-hour walk away. Vendors like him are known as "mairuwa" or "water owner" in the Hausa language.
"This is just something to do until you get a better business," said Adamu, 36, who migrated two years ago from northwestern Kebbi State, some 530 miles away.
"It's the type of work you can't do for long because it's hard on the body."
Thousands like him have fled northern Nigeria to escape both the rural poverty there and the Islamist insurgency in Africa's largest economy. The government says Boko Haram has killed more than 13,000 people since 2009. They killed at least 4,740 last year, more than double the number in 2013, Bath, England-based risk consultancy Verisk Maplecroft estimates.
On Sunday, at least 65 people were killed in the north-eastern city of Maiduguri during a Boko Haram assault on the capital of Borno State, according to a local militia member.
"Everybody is worried about Boko Haram, but the average Nigerian continues to see water as a private good, not a public good that has to be provided by the government," said Idayat Hassan, Director of the Centre for Democracy and Development, a research institute based in the capital, Abuja.
The water company's capacity is 210 million gallons a day compared with the 540 million gallons needed by Lagosians. Its potable piped water reaches about 7 million people. That leaves two-thirds of the city struggling to find safe water.
"Mairuwa are one of the most common forms of informal water supply," said Oluseyi Abdulmalik, a communications manager at WaterAid Nigeria. "They're filling the gap of what government's utilities should be doing."
Lagos water officials have developed a $3.5 billion plan to more than triple capacity to 745 million gallons a day by 2020 to meet a projected population of 29 million, according to Shayo Holloway, the company's group managing director.
The third-biggest killer of children under the age of five in Africa is diarrhoea, a disease that can – in nine out of 10 cases – be prevented by access to safe water and sanitation, according to WaterAid. Nigeria accounts for 11 per cent of all global under-five deaths, according to Unicef.
Nigeria isn't the only sub-Saharan African country struggling with shortages; 325 million people on the continent didn't have access to improved drinking water in 2012, according to a World Health Organisation and Unicef joint report last year. Dakar, Accra, Abidjan and Nairobi were cited as other water-stressed cities.
Today's water woes were deepened by a 2009 law that barred past distribution methods. Until then, residents who could afford a direct connection to the main line stored water in tanks and sold it to neighbours on a pay-as-you-use basis. When such reselling was made illegal, police seized vendors' tanks and disconnected them from the mains.
“The mairuwa took advantage of our stopping to bring water from outside,” said Ogundele Agbede, 80, a retired civil servant, who was forced to shut his sideline selling water after more than 30 years.
Vandalism of the water pipes remains frequent and even when the pipes are intact, the flow is as erratic as electricity supply in a country that suffers from daily blackouts.
At the Dustbin Estate slum, where the ground is soft from building over a refuse dump and swampland in the city's southern Ajegunle district, pipes paid for by development organisations are often broken. Sanitation in the community is poor. Residents dump bags of trash and faeces into an adjacent canal, looked on by grazing goats and emaciated cows.
“They sabotage this one a lot,” Tolulope Sangosanya, 32, the founder of LOTS Charity Foundation, said pointing to one of four pipelines and the faucets her group installed there. “Sometimes they go and break it in the middle of the night.”
In Otumara, many from Agbede’s association sunk boreholes to secure a new source to continue their trading business.
“Very unfortunately, 90 per cent of the boreholes are not drinkable,” Israel Akintimehin, 55, a pastor dressed in a Cleveland Cavaliers basketball vest, said in an interview at his Cherubim and Seraphim Church of Zion. “It's a very big irony: We're surrounded by water, yet we do not have good water.”
•Culled from Bloomberg