The world is facing a water and sanitation crisis, with 2.5billion people on our planet lacking access to a basic toilet. The global health and economic costs are huge. However, the crisis can be addressed, and there is an important and growing role for private enterprise.
There is perhaps no other resource in the world at once so valuable and so taken for granted as water.
The seas are rising, the planet's population is growing, cities are exploding with new people, and demand for food and resources has never been greater.
Growing middle classes and a rising group of super-wealthy mean the world is consuming everything, from meat to smartphones, at ever-greater speed.
In turn, demand for water - part of nearly every production process - is growing fast. Combine that with the effects of climate change, and making enough water available for every need and demand becomes increasingly challenging.
Caretaker Laxmi Bhujel, 29, prepares pipe fittings for her community's new water pump in Udayapur, Nepal. The mountainous terrain is prone to flooding and landslides in monsoon season. WaterAid/Mani Karmacharya
We hear much about the scarcity of water. What is often forgotten is that the planet has enough water to meet humankind's basic needs, that is, for drinking and keeping clean and healthy. What is critical is that it is managed carefully, and that basic needs are prioritised.
The importance of good sanitation
The Economist World Water Summit on 6 November was a welcome effort to bring together the public, private and nongovernmental sectors, spurring them into action on the world's water crisis.
For us at WaterAid, there's one more thing to consider. Toilet talk prompts nervous giggles and fidgeting. But with 2.5billion people on our planet without access to a basic toilet, it's never been more important to have that discussion.
You cannot have clean, safe water or a healthy population without good sanitation and good hygiene practices. These must go hand in hand.
This has never been more apparent than in the present crisis in West Africa. Ebola has wrought a devastating toll on Sierra Leone, Liberia and Guinea, its spread unchecked in early days because of health systems broken by years of civil war in Liberia and Sierra Leone.
Doctors and nurses never stood a chance of containing this catastrophic virus, spread through contact with body fluids including vomit and diarrhoea, when their hospitals and clinics did not even have running water and basic toilets.
The world has awoken to the crisis and badly needed help is now arriving. But simply treating the ill and containing the spread will not be enough. Once the situation allows, these affected countries must be helped to build clean water and sanitation systems that work reliably in the long term, or they will remain at risk of another health crisis.
When illnesses thrive
Beyond the devastation of Ebola, many other illnesses thrive in places without safe water, basic sanitation and good hygiene practices. Cholera outbreaks - unheard of in the UK since the introduction of sanitation systems in the nineteenth century - still occur regularly in much of the developing world. Typhoid fever, intestinal worms and the blinding eye infection trachoma all flourish in the absence of safe water and toilets. Even polio vaccination is less effective when children are suffering from chronic diarrhoea, often caused by dirty water.
Nearly 1,400 children under five - more than double the entire population of a large London primary school -- die every day of preventable diarrhoeal illness.
What's important is that this crisis can be addressed. A WaterAid policy paper that examines the transformation of Singapore and South Korea into modern, hygienic nations demonstrates that change is possible in just a few decades.
These East Asian 'tiger economies' began national education campaigns on cleanliness alongside massive planning, funding and building programmes for sanitation in the 1960s, when their GDPs per capita were similar to many Sub-Saharan African states.
By 1990, according to the UNICEF and World Health Organization's water supply and sanitation monitoring programme, both nations had achieved universal access and become well-off societies with strong economies.
World Health Organization economists have estimated that poor sanitation and water supply cost developing countries US $260 billion, or 1.5% of their GDP, each year.
Growing role for the private sector
There is an important and growing role for private enterprise to address the water and sanitation crisis and alleviate poverty, through funding, collaboration, and supporting domestic economies with investment. In exchange, corporations gain access to new markets, benefit from increased productivity and economic growth, and are better able to manage the risks that can come with operating in emerging markets.
WaterAid works with companies large and small, from corporate social responsibility programmes like H&M Conscious Foundation and the HSBC Water Programme, right through to small entrepreneurs setting up businesses as water pump caretakers or in waste management. We also do health-related research into water, sanitation and hygiene; the findings and subsequent action will benefit companies' work forces by making communities healthier and more productive.
As part of the new Sustainable Development Goals to be agreed by the UN next year, WaterAid is calling for a new, ambitious target of reaching everyone, everywhere with safe water and sanitation by 2030 as key to eradicating extreme poverty.
That means this generation. Not eventually, or even in the next 50 years.
The timing is crucial. The UN Secretary-General, Ban Ki-moon, has forecast that nearly half the global population will face water scarcity by 2030, with demand outstripping water supply by 40 per cent.
Corporations working in these water-scarce countries will feel the resulting strain of slowed development, poor health of their workforce, and increased tension in conflict-prone regions.
It's in everyone's interest to address the water and sanitation crisis. We have seen how great the costs are when we do not.
A version of this article first appeared in The Economist Insights.