Shire of Mundaring president David Lavell said enclosed netting was the smartest deterrent to prevent ducks entering the public swimming pool.
With duck numbers increasing steadily over the years, water quality had become increasingly difficult to maintain.
Staff trialled numerous ways to minimise visits from the unwanted guests, with limited success.
The Education Department and the shire shared the cost of the $60,000 project, approved by the council in August last year.
Mr Lavell said the additions would save thousands of dollars in pool-cleaning costs, water use and staff hours during the winter.
“The aquatic centre manager, Peter Duff, is retiring soon after more than 20 years in the role,” he said.
“It is fantastic he will be able to enjoy the last few weeks of the season without the ducks getting in his way.”
Mt Helena and Bilgoman aquatic centres close for the season on Friday, April 8.