The accident happened at 17:28 on Sunday when a child was found at the bottom of a pool.
Staff on site got the child out of the water and an ambulance was called.
The child was taken to hospital, where it was announced that the injuries were minor but that the child is still receiving intensive care.
It is the third accident in less than a year at Centralbadet.
Last year, two boys died in drowning accidents.
In February, a three-year-old boy drowned.
In mid-August, a four-year-old boy drowned.
Centralbadet is a bathhouse with an associated outdoor bath.