A spokesman for Tokyo Electric Power Co (TEPCO) said heavy rain during a recent typhoon has flooded one of the tank holding areas.
Asahi reports that the tanks were filled to about 98.6 percent of capacity, leaving very little space between the top of the water and the ceiling of the tank.
The latest leak was found during the transfer of contaminated water to another tank. TEPCO spokesman added that that the estimated amount of leaked water is around 4 tons.
In August, workers discovered that about 300 tons of highly radioactive water had leaked from another tank in the H4 area of the site and some of that water is believed to have reached the ocean.
After being accused of failing to report and covering up the radioactive leaks, TEPCO had recently reversed its denials and confirmed reports that Fukushima is leaking radioactive water into the Pacific Ocean. They plan to allocate around $500 million towards purifying the radioactive water and freezing the soil around the station in order to cope with the leaks.
If there is still somebody who doesn't know, the Fukushima nuclear power plant has suffered triple nuclear meltdowns and hydrogen explosions since it was hit by an earthquake and a tsunami, in March 2011.
Featured image credit: YT video screenshot