World Water Day is 22 March 2016.

In New Zealand, a number of organisations usually have events or activities to mark World Water Day. 
World Water Day has been observed from 1993 since its inception at the Rio de Janeiro UN Conference on Environment and Development in 1992.  It was set up by the UN General Assembly and is administered this year by UN-Water and UNDP.

The theme for 2016 is "Water and Jobs".
 

[The World Water Day website is "coming", 19 January 2016]