Workers at Japan's crippled nuclear plant are urgently seeking new places to store highly radioactive water as levels rise toward ground level in utility trenches near two reactors.

The Tokyo Electric Power Company said Wednesday that water levels were less than 35 centimeters from the top of the trenches. Japanese media said the levels continued to rise overnight and the water could begin spilling into the ocean within days.

TEPCO said it hopes to use a turbine condenser to remove some of the water at the number three reactor and more water may be transferred to other buildings at the Fukushima complex. The company hopes to have a water purifier in place by the middle of June.

The company is manually pumping water into the reactors to keep the nuclear fuel from overheating, but some of the radioactive water is leaking into the basements of the buildings. Three days of heavy rain caused by Tropical Storm Songda added to the problem, and the rainy season is just beginning.

Workers have been checking for leaks near a third utility trench where water levels have been falling, even as they rise at the other two.

Contamination from the plant remains a major concern for residents in the surrounding Fukushima prefecture. National broadcaster NHK reported Thursday that schools in the prefecture are urging children to continue to wear their long-sleeve winter uniforms during the summer months to reduce their exposure to the fallout.