The pool will close between June 4 and July 20 so that the major improvement works can be carried out.
The improvements - including renovation of the pool’s flumes, tower and slides - are being jointly funded by Mid Sussex District Council and Places for People Leisure.
Contract manager Tom Carter said: “The improvements reflect what our customers have been telling us they want to see at the centre. The leisure pool has always been a popular activity and we are excited to be able to deliver these works to show our ongoing commitment in providing great local leisure facilities for Mid Sussex.”
Contractors say the works will also include the removal of a falling rapids slide to create space for a new slide which will be introduced later in the year. The beach area will also be transformed, replacing the pirate ship with some new interactive water play features for children of all ages.
A spokesman for Mid Sussex District Council said: “During this period of work the leisure pool and lido will remain closed to the public. However, the works are taking place at this time to ensure the improved Leisue Pool is open for use during the busy summer months.”
To keep disruption to a minimum the fitness pool is expected to operate as normal during the works, as long as it is deemed safe to do so.
Council cabinet member for service delivery Gary Marsh said: “We are proud to continue to invest in our three leisure centres and this refurbishment work at the Triangle will ensure the leisure pool there is upgraded and can continue to be enjoyed by the residents of Mid Sussex for years to come.”
During the works alternative pools are available at The Dophin Leisure Centre, Haywards Heath and the Kings Centre, East Grinstead.