World Water Day, to be marked March 20, focuses this International Sanitation Year on the 2.6 billion people with inadequate access to toilets. UN estimates show that achieving its sanitation goal, agreed in 2000 — to simply halve number of people without access to a toilet by 2015 — would cost $38 billion, less than 1% of annual world military spending. That investment, however, would yield $347 billion worth of benefits — much of it related to higher productivity and improved health.