Lewis has spent four years at Asda, where she lobbied on employment and agricultural issues. Before that she was government affairs manager for Yorkshire Electricity Group.
‘The water industry has had a rough ride in the past year. There are lots of people who still have questions about how it is run today and whether there should be a radical rethink,' said Lewis.
As well as Yorkshire Water, Kelda owns US water supply business Aquarion.
The role was previously filled by Hedley Salt, who died last year.