It's so deja vu that I didn't even realize the news is for today. Another pipe with similar coupling as the one that leaked on Saturday leaked on Tuesday morning, July 12 in Japan, causing the contaminated water treatment system to stop.
So, when TEPCO did the repair on that joint on Sunday their time, and said there were at least 6 others like that, the company didn't bother to change the other 6 at the same time.
So I guess there may be at least 5 more leaks to go.
From Yomiuri Shinbun (12:17PM 7/12/2011):
TEPCO announced on July 12 that the contaminated water treatment system stopped at 8:51AM at Fukushima I Nuclear Power Plant.
A leak was found near the coupler that joins the hose that injects chemical to AREVA's coagulation/coprecipitation unit. The cause of the leak is being investigated, and it is not known when the system will be re-started. The cooling of the reactors using the treated water continues regardless.
According to TEPCO, a worker noticed the leak at about 8:40AM, and manually stopped the system. The leak was near the spot where 50 liters of contaminated water with chemical had leaked on July 10. The PVC coupler had been replaced with a metal one, and the system was re-started after 13 hours. It is not known if today's leak has anything to do with the previous leak nearby.