It would know in about a month if its application was successful.
If it did gain the grant, the money would go towards joinery work and repainting the exterior, Mr Gillard said.
At the moment the group was working on taking up the particle-board floor and polishing the original tongue-and-groove floor.
As well, it was planning costings for the building's interior renovation.
In addition to the grant, the Rotary Club recently held a working bee at the courthouse, during which 15 of its members helped strip the 1950s interior lining.
Another indication of the level of community support was the advice being provided by Carterton architecture firm Architecture Robinson Crimp, which was helping design new steps and advising on paint colours, Mr Gillard said.
The Carterton Courthouse was built in 1884 and while not heritage-listed, it is listed on the Carterton District Council schedule of heritage buildings.
Once fully renovated, the courthouse will act as a hub, with community agencies making use of the space.