JEPARIT Water Watch wants Wimmera water authorities to investigate the health of Lake Hindmarsh as its salinity increases.
The six-member group monitors the Wimmera River between Tarranyurk and Picnic Point, as well as the lake.
The group will invite Parks Victoria and the Wimmera Catchment Management Authority to inspect the waterways at its next meeting on September 11.
Water Watch member David Livingston said the lake's salinity had almost tripled its healthy level.
"We just want them to come up and have an inspection and have a look at what is happening here," he said.
"The salinity in the river is quite good because we are having a bit of water running through it, but the lake's salinity is getting really high again.
"The lake is only a couple of feet deep in the deepest part, so we want about five inches of rain."
Mr Livingston said water authorities had failed to keep noxious reeds around the river and lake under control.
"Since they have cut out grazing, the reeds are getting out of control near the river and lake," he said.
"It will be hard to access the river for miles soon because there are phragmites growing up all around the banks. When it dies off, the decaying matter of old phragmite reeds will go in and pollute the river."
Mr Livingston said the river and lake were important for the community.
"It is about the environment and public entertainment; it is about the fish, the birds and the bees," he said.