The water is the result of typhoons and downpours that have filled barriers around radioactive waste water tanks.
TEPCO has been storing the most contaminated rainwater in tanks and in the basement of a turbine building.
But with Typhoon Francisco set to hit Japan's mainland over the weekend, the tanks are full.Japan's nuclear regulator has approved moving the tainted water to 3 underground pools. The pools have a total capacity of about 9,000 tons.
TEPCO stopped using the pools after similar models leaked in April. The utility now says it has no other option but to use them.The utility also says it found 140,000 becquerels per liter of Beta-ray emitting radioactivity in an onsite ditch on Wednesday.
The radioactivity has doubled since the previous day.
TEPCO says it is transferring the contaminated water to a tank.
Oct. 23, 2013 - Updated 22:39