Ms McNaught said the septic tank filtration system had not been working properly for some time and it was not big enough to accommodate the extent to which the public toilets were used.
She said the existing rainwater tank had not been sufficient for the flushing of the toilets and in 2013 the council had installed an additional 30,000 litre tank.
"This required refilling a couple of times over summer 2013/14, but in summer 2014/15 it had to be refilled four times."
It was thought that the high water usage had been campers refilling their campervan tanks.
"[The tank] is also badly affected by frequent inflows from ground water. The water table is only about 300mm below ground level, so the solids tank floods almost constantly."
The estimated cost to build a new system that could cope with the toilets' high usage would be around $40,000.
Ms McNaught recommended in her report to withdraw the toilets from service and replace them with a two cubicle self-contained dry vault toilet with holding tank, with an estimated price tag of $37,000. This would leave the single toilet inside the fire station building on the septic tank, which would be manageable.
The new toilets could be installed and completed before the end of January, Ms McNaught said.
"This is the preferred option, both because it can be completed in time for the main part of summer 2015/16, and because the ongoing costs will be limited to annual pumping without additional water supply costs."
The self contained dry vault toilets would be the same model as a single one which is being manufactured for north Tora. This is expected to cost $19,000 and was on track to be installed in time for Christmas.