Fortified by a faith in God and a Guinness stout -- or a tot of something stronger -- Ololade Rabiu reckons she must have dug hundreds of wells in her time.

But the 46-year-old mother of six is a rarity in Nigeria, where forging deep into the red earth to find precious drinking water has historically been a male preserve.

"I am extremely happy that I am the only woman so far in this profession of well-drilling. I love and enjoy it," she told AFP at her home in Igbogbo, about 40 kilometres (25 miles) east of Lagos.

"There is no well I cannot drill or enter," she said proudly.

Megacity Lagos and its surrounding state are crippled by over-burdened and neglected infrastructure, with safe, clean drinking water in particularly short supply.

A study by the Lagos State Water Corporation found that the city's 18 million people needed 540 million gallons (2.5 billion litres) against actual production of just 210 million gallons in 2010.

It has vowed to dramatically increase production to 745 million gallons per day by 2020, by which time the city is expected to be home to 29 million people.

But in the meantime, households are forced to rely on tanker deliveries for their water or private wells.

Purification to eliminate disease is not guaranteed and street vendors selling "sachet" water in cellophane bags are a common sight -- as are the discarded empty packets on the streets.

- 'The well woman' -

The shortfalls in public supply mean there is plenty of business for well diggers like Rabiu, who first began drilling for water in 1997.

She learnt her craft from her Ghanaian second husband, Daniel Ajiraku, and has since carved out a niche for herself along with a nickname in the Yoruba language: "Mama Kanga" -- "the well woman".

"The beginning was difficult but now I thank God that I have overcome my initial fright and I have made a success of my chosen career," she explained.

"Daniel taught me all the rudiments of well-drilling: how to locate the water bed, determine depth, how much to charge, the implements to be used and how to overcome challenges."

Neighbours and clients are full of praise for her ability, which once saw her drill to a depth of 130 feet (40 metres) in the Akute area of Ogun state.

"She drilled my well more than seven years ago and she did it so well that I have so far had no problem with it," said Ben Kunle Omodein, from Igbogbo.

"She is gifted in the art of well-drilling. I am sure she does it better than many men," said her former landlord, Yisa Abdul.

- 'Our hero, our mother' -

Rabiu's third husband, Saliu, died at the age of 64 last month but she said that the setback would not stop her working.

"Life must continue. I cannot allow the death of my husband to kill my career," she said.

Rabiu's children, one of whom lives in Spain, have followed their mother into the well-digging business.

Fourteen-year-old Kobina proves the point by jumping into a nearby water-filled well, only to re-emerge a few minutes later.

As for the job's male bias, Rabiu, who is from Ile-Ife in southwest Nigeria and originally trained as a designer, said she had never let her gender stop her from doing what she wants in life.

Rabiu's living room is strewn with the tools of her trade: a wheel-barrow, water-pumping machine, a hose, spade, iron bars, shovels, buckets and two generators.

The job is dangerous and back-breaking, she admitted, but said that her faith in God -- and a Guinness, gin or whisky -- had helped her overcome the challenges.

Nothing, she said, gives her as much pleasure as digging wells.

"I feel elated when we have a meeting of well-drillers in Lagos and I am the only woman in the midst of hundreds of men.

"I am well respected because they all see me as their mother. They are my children," she added.

Yusuf Mainasara, a well-driller from Niger, agreed.

"'Mama Kanga' is our queen, our hero and our mother. We are really proud of her," he said.