Sanjay Wijesekera speaks to press at the Sanitation and Water for All Ministerial Meeting, Addis Ababa, Ethiopia, March 15, 2016

When it comes to water, sanitation and hygiene, the new Sustainable Development Goals are not going by half-measures.

The SDGs are aiming for 'universal and equitable' access to safe water, sanitation, and hygiene. In other words, for every single person on earth.

In this, they are unlike the Millennium Development Goals which aimed only to reduce by half the proportion of the global population that didn't have adequate drinking water, or have or use toilets.

The MDGs left 663 million people without improved drinking water in 2015, and 2.4 billion people - roughly one-third of the world - without toilets.

In 2015, some 800 children under 5 years old died every day from diarrhoeal diseases caused by the lack of safe water, sanitation and hygiene. Around 159 million children globally were stunted, a condition linked to open defecation.

How do we get from here to there?

Representatives of some 50 countries are in Addis Ababa this week, with the UN, civil society and experts, at the Sanitation and Water for All Ministerial Meeting precisely to plan how to move forward on universal access.

We at UNICEF see this as a crucially important challenge. Simply put, the goals on nutrition, health, education, poverty and economic growth, urban services, gender equality, resilience and climate change cannot be met without progress on water, sanitation and hygiene.

It is clear we can't work in the same old way.

What we have to do is:

1.Focus on those furthest behind. We can no longer leave out the poorest and most marginalized. The rural poor; those who live in urban slums; ethnic minorities; the disabled; and many women and children were among those left out of the MDGs. We must reach them.

2.Ensure good governance and accountability. It will come down to stronger and better policies, institutions, financing, monitoring systems and capacity development. In Addis, we will agree on how make sure these are in place in each country.

3.Address the impact of climate change: Nearly 160 million children live in severely drought-prone areas, and half a billion in flood prone areas, mostly in Africa and Asia. These climate-linked events exacerbate water scarcity and damage water and sanitation systems, increasing the risk of diarrhoea outbreaks. Other water-borne diseases such as malaria, dengue, zika, and cholera are set to rise with higher temperatures. We must deal with climate change, especially for those already most vulnerable.

4.Use innovation, testing and data. It is 2016, and we have better technology than in 2000. We can test to ensure that safe water is flowing from 'improved' water sources. We can gather data to help governments pinpoint the populations left behind. And we can use new technology to bring better and cheaper toilets, and better and safer water to the millions who don't have them now.

Addis must be our springboard to action, because no one should have to wait for years and years for safe water, proper toilets and better hygiene.

(A version of this article was run by IPS News , March 15, 2016)