A Kaitoke resident has concerns about increased stormwater discharge from Whanganui Prison into a creek between Wiritoa and Pauri lakes.
The woman swims in Lake Wiritoa and said she had always had an issue with the stormwater but believed she was powerless to stop the consent to increase the stormwater discharge into the creek.
"The water in both lakes sits and doesn't move until around the middle of July," she said.
"A property developer on Kaitoke Rd sold sections, and they had to abide by rules and not drain anything into the lakes - why is it different for government departments?"
Department of Corrections spokesman Rob Hunter said the prison had submitted a resource consent application to Horizons Regional Council seeking to increase the prison's stormwater discharge for the next 34 years.
"This request is part of the prison's normal operation and is a renewal of the existing consent," Mr Hunter said.
"The increased discharge is directly linked to rainfall and reflects the maximum capacity of the existing stormwater system and will only occur during storm and heavy rainfall events."
He said the application was going through the formal Resource Management Act process and Horizons would make a decision in due course.
The stormwater to be discharged into the waterway is collected from the carpark, roadways, paved areas and roofs via guttering.
Mr Hunter said stormwater testing during storms or rainfall events was done to check what was in the water.
"In particular, testing is done checking for organics, heavy metals and hydrocarbons. Recent tests show that nothing unexpected was found in the stormwater."
The prison had submitted these results to Horizons as part of the application.
The woman was concerned that, over the years, she had seen frothy, milky water discharging into the creek.
Mr Hunter said it was the first time the matter had been brought to his attention, and believed it could have been because of the speed of the water leaving the pipes.
The woman said the lakes only overflowed in the winter after heavy rains. In other months the water sat in both lakes.
A man who has a bach at Pauri Lake said if the drain that the wastewater fed into was cleared out, there would not be so much water backed up.
"My concern is that Corrections do not discharge stuff from their concrete plant. When it's really raining down, the two pipes fill the lakes quickly and it floods our bach," he said.