With heavy rain battering the Taupo region recently, Lake Taupo is nearing 100 percent capacity.
With more wet weather forecast, preventing the lake from filling up even more may be difficult.
Measuring levels show the lake has less than 25 centimetres left before it reaches capacity.
If it continues at its current rate, service holes, stormwater drains and sewerage pipes could all take a hammering.
Waikato Regional Council's Adam Munro says the situation is worrying.
"We've had a lot of rain in that catchment over the last three or four months. We've got 30 tributaries that flow into Lake Taupo and there's only one outlet."
But he says they are working to find a solution.
"We were with Mercury [Energy] on agreed procedures around how we can either change the gate control at Lake Taupo or we can communicate that out to the public to make sure they aren't aggravating the situation for example by not trampling on sensitive dunes and vegetation."
One of the biggest impacts of Lake Taupo filling up so quickly is the erosion happening along the shoreline.
In recent days the Waikato Regional council have had to put boulders in to prevent it coming back any further.
Some of that erosion is clear to see but the other impacts of a very full lake also have locals worried.
Tom Northcroft has been living on the shores of the lake for 68 years.
"We've lost this good fishing strip that used to run here," he says.
But while the current levels are concerning, he's confident they'll go back to normal.
"I live here, right opposite the river mouth and I've seen it higher than this before in recent years, then it recedes over summer and gets back to a reasonable level."
But with poor weather expected to continue, authorities will now be up against it to ensure the Great Lake stays just that.