Ms Soal, who has worked as the director of strategy and policy at the Waitaki Irrigators' Collective for the past eight years, will take up the role in late February.
She replaces Andrew Curtis, who has been chief executive for nearly 10 years and is leaving to start two new ventures.
Ms Soal previously worked as a policy adviser for the Ministry of Social Development, at the Ministry of Justice, and at law firms in New Zealand and England.
She has a master of arts in politics, a first-class honours degree in politics and a law degree from the University of Otago.
She is working towards a PhD in geography which focuses on freshwater governance in New Zealand.
Ms Soal said freshwater management and governance was a ''massive'' issue for New Zealand and had escalated in terms of public importance over the past few years. The opportunity to be part of the discussion around that, at national level, was very exciting.
She has had a close association with IrrigationNZ, having served on its board from 2011 to 2016 while the Waitaki Irrigators' Collective also maintained a close relationship with the organisation.
Although there were many sides to the debate on water quality and allocation, everyone coming into that discussion came from a place of genuine concern.
Everyone needed to be listened to in order to come up with solutions that tried to address those concerns, she said.
She always approached everything she did with honesty and integrity and she hoped to bring that to the role.
While excited about the new opportunity, it was with some sadness she was leaving WIC, which was ''amazing'' to work for. The directors and farmers she worked with were very knowledgeable and their leadership in the industry was ''incredible''.
They had amazing foresight and were very progressive in everything they did and it had been a pleasure working with them, she said.
IrrigationNZ's head office is at Lincoln and Ms Soal intends continuing to live in Oamaru and work remotely.
She said she loved the North Otago community and it was also conveniently situated between the two largest irrigated areas in New Zealand.
IrrigationNZ chairwoman Nicky Hyslop said Ms Soal had a strong background and deep understanding of both politics and water and the challenges and opportunities that communities and irrigated farmers faced.
''IrrigationNZ will benefit from Elizabeth's practical understanding of the management challenges 'on the ground' combined with her political and advocacy experience,'' she said.
