A giant metal tube will soon start playing an important role in south-east Queensland’s water security.

The latest step in a multi-phase project to upgrade Seqwater’s Landers Shute Water Treatment Plant is underway.

Experts are on hand to install a new storage silo filled with thousands of kilograms of lime, due to come into operation next month.

The $7 million stash of lime will improve the plant's capacity to cope with water quality challenges created by heavy rainfall.

The plant draws water from Baroon Pocket Dam to provide 75 per cent of the Sunshine Coast's drinking water.

It can also be used to send water as far north as Noosa and to Brisbane's northern suburbs, through the South-East Queensland Water Grid.

Acting CEO of Seqwater, Jim Pruss, said the lime upgrade would improve the plants’ reliability and production capacity in all weather conditions.

“Landers Shute has proven to be one of south-east Queensland's most efficient water treatment plants,” Mr Pruss said.

“In the 2011 floods, the plant played a vital role in supporting Brisbane's water supply needs when the Mt Crosby Water Treatment Plants went offline.

“It's important that we continue to maintain and improve our water infrastructure and provide a reliable drinking water supply to our region's growing population, no matter what Mother Nature throws at us.”

The upgrade also includes a new lime saturator, a new acid dosing system and post lime dosing lines.

“Lime is crucial to the water treatment process,” Mr Pruss said.

“It is added to drinking water at various stages to adjust alkalinity and correct pH levels and this is especially important when we face increased water quality challenges during heavy rainfall events.”