With his leaving date yet to be confirmed, Powell, who started at the plumbing products group in 2017, will remain in place for now.
At paper and packaging group Mondi, he will succeed Andrew King as CFO after he was promoted to CEO.
At Ferguson, Powell missed out on a similar promotion as the company chose the chief executive of its US arm to be its new group CEO as it slowly moves towards a primary listing Stateside.
Ferguson, which recently was forced by the coronavirus to make a U-turn on its dividend and on its immediate plans for a full listing on Wall Street, said it has begun to search for a new finance chief, with the new role to be based at its US headquarters in Newport News, Virginia.
Over at Mondi, King said Powell “has significant financial and strategic experience having been chief financial officer and an executive director of a number of large international listed companies”.
Analysts at broker Peel Hunt said his departure from Ferguson “comes as no surprise given the shift of the business to be solely North American focused.
“His departure date will be confirmed in due course but an orderly handover is planned. While the market saw him as a very safe pair of hands and he will be missed, this comes very much as part of the group's evolution.”
Shares in Mondi were up 2% to 1,431.5p on Tuesday morning, while Ferguson's were up 3% to 6,410p.