Richard Moriarty will leave Affinity Water at the end of January 2015 after being appointed as the new chief executive of the Legal Services Board, the regulator for the legal services market in England and Wales.
Affinity Water chairman Philip Nolan said: “Over the time that he has been with us, Richard Moriarty has made a valuable contribution.
“He was instrumental in leading the team’s successful engagement with Ofwat in the final stages of the price control, culminating in Affinity Water being awarded enhanced status.
“As an enhanced company, we have been able to start the planning process earlier for our AMP6 programme and we are well placed to deliver our business plan commitments.”
Moriarty’s departure comes after chief executive Richard Bienfait announced his shock departure from Affinity Water at the start of October.
A search for Bienfait’s successor is underway and the water company said it will make a statement “in due course”.
Affinity Water was one of only two companies to be fast tracked by the regulator for the current price review, PR14, alongside South West Water.