Mayor Sarah Schmerl said the maintenance - valued at over $2 million - had been in the works for some time, after the St Helens Hospital fell victim to severe flooding in recent years.

"St Helens has suffered from drainage issues for many years," Cr Schmerl said.

"Quite a number of times the St Helens Hospital has flooded and forced the evacuation of patients and staff.

"The flooding has also seen sewage flow up into the kitchen in previous events and it's even flooded homes."

Cr Schmerl said a new stormwater system in the main street was a development that would serve future generations.

"This has been a major infrastructure expense and something that will significantly better the water congestion in the region," she said.

"It's an investment for the future and will serve the region for many years to come.

"We're very grateful to the local community who have been patiently waiting while these works are carried out."

The stormwater maintenance work began on April 14 and has an official completion date of October 31.