The appointment reinforces Thames Water's commitment to CSR and comes just a month after the group announced it was rolling out a major programme to improve consistency on CSR issues throughout its operations across 46 countries (PRWeek, 23 August).
Aylard joins as CSR director from Burson-Marsteller - Thames Water's retained agency - where he acted as European environment director and head of CSR.
The former adviser to the Prince of Wales will report to Thames Water chief operating officer Jeremy Pelczer when he starts next month.
Thames Water global media relations manager Cathy Little said: 'We believe CSR differentiates us - it's something we're extremely keen to do more of,' she added.
Aylard will retain a non-executive role at B-M, which is set to remain on Thames Water's roster.
B-M confirmed Aylard's deputy Nick Bent would assume responsibility for the five-strong CSR unit when Aylard departs.
Prior to B-M, Aylard acted as an independent consultant on environmental issues and change management, during which time he worked with Thames Water.
He also helped found Business in the Environment and The Prince of Wales' Business and Environment Programme for business leaders.