The £11m development is being built within the centre, on the former indoor 3G football pitch and includes an eight-lane, 50m swimming pool with moveable floors and beams and a 500-spectator pool viewing gallery.
A health suite with sauna, steam and jacuzzi will also be created, alongside swimming education rooms and expansion to the fitness suite and function rooms.
Croydon-based DESCO is the M&E consultant on the pool project at the MSA Sports Ground on Allard Way.
Jonathan Marston, managing director of Galliford Try East Midlands, said: “This is the kind of public facility that makes a real difference to the people of the area and we look forward to creating a building that will be used and enjoyed by the local community for years to come.”