Looks like another electrical problem with the lavatories.
"Toilets shutdown force B-787 returns to Moscow
Malfunctioning cabin toilets have forced a Japan Airlines Dreamliner bound for Tokyo to return to Moscow. The airline suspects an electrical problem.
Airline officials say the mid-flight malfunction occurred on Wednesday afternoon.
The jetliner was carrying 151 crew and passengers when it changed its destination to an embarking airport in Moscow and landed safely 5 hours later.
They say the plane was fine on the outward journey from Tokyo to Moscow.
Dreamliners were grounded earlier this year after a string of battery problems. But the airline insists the two problems are unrelated.
Oct. 9, 2013 - Updated 23:08 UTC"
Toilets shutdown force B-787 returns to Moscow -NHK WORLD English-