Work is due to start on a £26m project to improve the quality of sea water at Weston-super-Mare.
At present sewage returned to the sea at Weston and nearby Uphill is clean enough to meet current legislation.
But under the revised Bathing Water Directive which comes into force in 2015 the same water samples would be classified as "poor".
Wessex Water said it hoped the work would be completed two years ahead of the directive coming into force.
"Our aim is to ensure we have done everything to improve the water quality to ensure local beaches remain designated bathing waters and continue to attract tourists to the North Somerset area which the local economy so heavily relies," the spokesman added.
The utility company says the work at its Weston sewage plant involves increasing the secondary treatment and ultraviolet (UV) disinfection capacity of the plant.
It also plans to increase stormwater capacity to reduce the likelihood of sewage being discharged into rivers and the sea during periods of heavy rainfall.
Machinery and materials are due to be delivered to Weston sewage works next week with construction getting underway in May.
The work is expected to be completed by December 2013.