Waters was born in Winnipeg, Canada, grew up in Brisbane and as of 2010 lived in Bardon with her partner and their daughter. She has a Bachelor of Science and a Bachelor of Laws from Griffith University and a Graduate Diploma in Legal Practice from the New South Wales College of Law. From 2000–2001 she was a Legal Researcher at the Queensland Land and Resources Tribunal (predecessor of the Land Court of Queensland), from 2001–2002 a Lawyer at Freehills, and from 2002–2011 was a Lawyer with the Environmental Defenders Office.
Waters was the Convener of the Queensland Greens North Brisbane Branch from 2006–2007.
She ran first on the Queensland Green Senate ticket at the 2007 federal election and received 7.3 per cent of the vote, an increase of 1.9 percentage points, failing to gain election.
On 6 May 2015, Waters was elected unopposed to serve as Deputy Leader of the Australian Greens, serving alongside Senator Scott Ludlam. This followed Christine Milne resigning her leadership of the party.