RECENTLY installed flood gauges in the Mary River, made from galvanised steel, will rust quickly according to a Maryborough flood crusader.
Graham Wode has campaigned tirelessly for better flood mitigation for the Maryborough area.
He said the four alert gauges installed after the 2013 floods were made from galvanised steel, despite the water quality of the area.
"It's a very well-known local fact that Tinana Creek water is corrosive, that irrigators on that system use stainless steel or plastic in preference to galvanised," he said.
But Fraser Coast Mayor Gerard O'Connell said cost was an issue, and the current gauge construction worked fine.
"To make the units entirely from stainless steel would make them so expensive that they would be out of the reach of council," he said.
"In the 20 years the units have been operating they have needed minimal maintenance."
Mr Wode said a flood gauge on Churchill St had a galvanised pipe, which had failed after the 2011 floods and was then replaced with stainless steel.
He also said a similar galvanised pipe failure occurred at a Tinana Creek gauge after the 2013 floods.
"This replacement water-line pipe was replaced about December 2013 with stainless steel," Mr Wode said.
Cr O'Connell said there were 14 alert monitors across the region, with some installed in 1995.
"The units installed in the '90s were unpainted galvanised steel," he said.
"The recently installed units are powder-coated galvanised steel."
Mr Wode said the rust wouldn't be likely to affect the flood readings straight away.
"It won't affect their working condition until the end falls off it," he said.
Cr O'Connell said the units were made and installed to Australian and Bureau of Meteorology standards.
"The company which supplies and installs the units for council also supplies and installs the units around Australia and across the world," he said.