The water company was the only one to challenge the pricing determined by the regulator for the 2010-15 period. The case will now be reviewed over the next six months by the Competition Commission.
It is only the fourth time that the Competition Commission has been called upon to determine water pricing since price controlling was introduced 20 years ago.
The US firm will act as sole counsel for Bristol Water throughout the procedure.
Stephen Tupper, a competition partner at the firm, said: “We have a longstanding relationship with Bristol Water and the water industry generally. That being said, we recognise what a statement of faith in our work this represents.
“We’re relishing the challenge.”
Tupper joined GTM from Watson Farley & Williams last September as part of a hiring spree at Greenberg Traurig’s newly launched London office (10 September 2009).
Ofwat launched a tender process for its first-ever legal advisory panel last year (19 November 2009).