A water firm has had one water pollution incident reported against them every day on average for the past four years.
Southern Water had nearly 1,500 incidents reported to the Environment Agency between the beginning of 2010 and the end of 2013.
But a spokesman for the firm said that serious pollution incidents had reduced by more than a quarter during the period and that £3 billion will be spent on improving the water treatment network in the next five years.
The water company also said it aims to have no serious pollution incidents affecting local rivers, streams and beaches caused by their operations by 2020.
Nearly 800 of the incidents reported to the Environment Agency were deemed to have caused an impact on the surrounding environment.
Southern Water, which made a profit of £331 million in 2012/13 – up from £271.6 million in 2011/12, has also paid out more than £55,000 in fines over the past four years.
The firm has invested £1.8 billion across their whole region in their current five-year plan up to 2015.
A Southern Water spokesman said: “We take our environmental responsibilities seriously and have successfully reduced the number of pollution incidents which have had an environmental impact in Sussex by more than a quarter over the past four years.
“We achieved this with an action plan which included targeting our investment better, improving maintenance and providing extra training for staff.
“Between 2015 and 2020, we will invest more than £3 billion to maintain and develop this vast network and continue to improve services for our customers.”
The Environment Agency last month announced they were investigating the leaking of 900,000 litres of sewage into The Ouse in Lewes following the collapse of a tank during fierce storms in December.