It's hard to believe that already a year has elapsed since the UN agreed a set of new global promises to leave a safer, healthier, cleaner and more prosperous world to the next generation. If we remain focused and determined, that day will remain in history as the day we set out to end extreme poverty.
These UN Global Goals on Sustainable Development represent hope for change: a chance to even inequalities, tackle the difficult and increasing impact of climate change, and create a better world.
In his first review of progress on the Global Goals this summer, UN Secretary-General Ban Ki-moon warned that one in eight people in our world still live in extreme poverty, and that nearly two billion people live in areas of water scarcity. More than 650 million people worldwide do not have a reliable source of clean water, and more than 2.3 billion do not have the dignity of a safe, private toilet in which to relieve themselves.
But he also called our first year of working toward these Goals a good start, and indeed there are reasons for optimism, particularly when it comes to Goal 6 to deliver water and decent toilets to everyone, everywhere by 2030.
Here are some of the reasons we know we're making progress on water and sanitation - and why it's so important to press on to finish the job.
1. Since 1990, 2.6 billion people in the world have gained clean water drinking water. WaterAid has helped reach 23 million since 1981 - including communities like this one in Ethiopia, where the taps were turned on in December.
2. Since 1990, some 2.1 billion have acquired access to decent, private toilets. WaterAid has helped reach 21 million people with sanitation since 2004.
Neelama Kumari, 9, learns about hand-washing beside a new latrine block at Government Primary School, Harijan Colony Malan Hore Veena, Tharparkar, Pakistan. WaterAid/ Mustafah Abdulaziz
3. The number of children dying from diarrhoea has gone down dramatically between 2000 and 2015 - from 1.2 million to half a million a year. About 58% of these deaths are because of dirty water, poor sanitation and poor hygiene.
4. Our innovative work with partners has produced incredibly creative ways to address the sanitation crisis in a sustainable way , including using biogas systems to provide cooking fuel and heat for homes and cafes like these:
A worker preparing food at a biogas cafe, Addis Ababa, Ethiopia. WaterAid/James McCauley
5. ...as well as providing work -- for example, these pit-latrine-emptying Gulper trucks and the small companies that make money from them:
Julius Chisengo, Group Operator UMAWA, 48 (right) and Cleophas Shinga, Group Operator UMAWA, 49 (left), empty the contents of a pit latrine at Kigamboni Ward, Temeke Municipality, Dar es Salaam City, Tanzania. WaterAid/ Eliza Deacon
6. And we can see the map changing, showing where progress is being made.
These are massive achievements worth celebrating, and they demonstrate that success is possible on these foundations of development. WaterAid research has shown it too: Singapore, South Korea and Thailand all managed to deliver sanitation to everyone within a generation, when leaders made it a priority, planned and funded it accordingly, and got everyone in the country on board in mass campaigns.
Cities like Visakhapatnam in India, and Kumasi in Ghana, have come up with innovative ways to deliver better sanitation, through public campaigns, the construction and promotion of public toilets and most of all, commitment and focus from high levels of government.
Despite this progress, there remains a devastating water and sanitation crisis: the 315,000 children under 5 who lose their lives to preventable diarrhoeal illnesses each year do not often make newspaper headlines. At present rates of progress, only one-third of people in Sub-Saharan Africa will have a safe, private toilet by 2030.
These should not be hard-sell arguments. Water and sanitation are good for health. They are good for the rights of women and girls who are freed from the tedious and often dangerous burden of walking long distances to find water, and the humiliation and risk of trying to find a safe, private place to relieve themselves. And they are good for economic prosperity, by enabling communities to become healthier and community members to earn money, become more educated or to spend more time caring for their families.
The UN Global Goals were set up with the understanding that they are all interlinked: A country cannot properly achieve economic progress if its children are ill, or hungry, or unable to attend school, or do not survive infancy. There is no sustainable progress if water resources are not managed sensibly, or if wastewater is not treated. And we cannot create a fairer, better world if the poorest and most marginalised - including the elderly, the disabled, those in remote or rural locations, or who are part of disadvantaged indigenous or caste groups - are still being left behind.
Failing on water and sanitation also means failing at gender rights, education, maternal and newborn mortality, and child health and nutrition as well as economic growth.
For those of us working in development, this is both a terribly frustrating and enormously heartening time - we are, as Bill Gates likes to say, 'impatient optimists.' We know this transformation can happen. We just need the political will to get there, and the money dedicated to the task.
This post is part of a series produced by The Huffington Post to mark the occasion of the one-year anniversary of the adoption of the Sustainable Development Goals (SDGs, or, officially, "Transforming Our World: the 2030 Agenda for Sustainable Development"). The SDGs represent an historic agreement -- a wide-ranging roadmap to sustainability covering 17 goals and 169 targets -- but stakeholders must also be held accountable for their commitments. To see all the posts in the series, visit here.