Africa is a continent of astonishing potential. But if it is to build the future its citizens deserve, we have to see increased effort to remove the barriers holding it back. None is greater than poor sanitation – a shadow hanging over the lives and prospects of hundreds of millions of people on the continent and across the world.

Nearly one billion people globally are forced to defecate in the open. As many have to live with inadequate sanitation. Both situations lead to the contamination of water and food and the spread of disease. The costs – human and economic – are huge which is why it is so disappointing that the Millennium Development Goal on sanitation was the one furthest from being achieved.

The impact on health of this failure is enormous. Diarrheal diseases, caused overwhelmingly by poor sanitation and unsafe water, remains one of the top ten causes of death worldwide according to the WHO, killing 1.5 million people in 2012.

The damage from a lack of sanitation goes far beyond health. The lack of toilets puts the personal safety of girls and women at risk. It’s one of the major reasons why so many girls drop out of school, robbing them of an education and their communities of their talents.

It’s not just a human tragedy but a huge economic burden on already hard-pressed countries. New research prepared by LIXIL and Oxford Economics has put the annual cost of poor sanitation for low and middle income countries at $222.9 billion. These cumulative costs include those from early loss of life, providing health care and the impact on productivity of sickness.

It is the largest countries like India, the research shows, which shoulder the highest national cost burden. But if you look at these costs nation-by nation as a share of GDP to work out their impact on a society, then countries from sub-Saharan Africa make up half the top ten. In Niger, poor sanitation costs 2.7% of GDP and the figure is nearly one per cent across the continent as a whole. Africa simply can’t afford this loss.

Even more worrying is that the research shows these annual costs for Africa have risen by 24.5% in the last five years and now stand at over $19 billion. It also underlines the terrible toll poor sanitation is taking across the continent by revealing that premature deaths account for 75% of these total costs in Africa compared to just 55% globally.

This is why sanitation and hygiene must again figure high on the agenda [this week] as Japanese and African heads of state gather in Nairobi for the Tokyo International Conference on African Development and in Stockholm as businesses, political leaders and others gather for World Water Week.

This complex challenge is made more difficult because sanitation solutions used in developed world cannot be transplanted to the slums or rural areas of Africa. The infrastructure is too costly to build and maintain and too wasteful of resources. Water across many parts of the continent, for example, is already scarce and becoming scarcer because of climate change.

It is not all bleak news. Not long ago Bill Gates rightly said not many of the smartest people were involved in finding sanitation solutions for those in low income countries. That’s no longer the case, thanks in part to the role he has played in pushing it up the global agenda.

I am proud that LIXIL is bringing all its experience as a world-leader in water technology to help find solutions. With a wide variety of partners, we are developing affordable and effective solutions which will meet the needs of poorest communities.

We introduced, for example, the cost effective and hygienic Safe Toilet (SaTo) products in 2013 and over one million have now been installed in Africa, Asia and the Caribbean for as little as $2 dollars a unit. They are helping transform sanitation and such is the demand and need, we aim to have installed 20 million by 2020.

Considerable progress has been made in recent years across the industry in recognising the challenge. But there is no time to waste. Every year the cost in human misery and lost prosperity keeps rising. Overcoming this challenge requires even greater effort and co-operation from governments, businesses, and civil society.

Governments must commit to national sanitation strategy with stretching but achievable targets backed by increased funding – public, private and a mix of both. National efforts must also include a new emphasis on education so the citizen understands the need to use and look after sanitation facilities when they are provided.

Innovation and partnership are absolutely critical. We need more innovation in technology and delivery so we find new, affordable and sustainable ways of bringing sanitation to those at the bottom of the pyramid. This will be encouraged by more collaboration and public-private partnerships so knowledge and experience is shared.

There are exciting developments going on in Africa and round the world to provide sanitation to the communities who need it most. By stepping up our collective efforts, we will remove a huge barrier to a better future for this continent.

Mr Kinya Seto is President & Chief Executive Officer of LIXIL Group Corporation.