The fire-fighting system in an ancient Tibetan town in Shangri-La county which was destroyed by a blaze was shut off at the time, Chinese officials say.
The equipment was closed down to prevent pipes from bursting in below-freezing temperatures, the local fire brigade said on its microblog.
Nearly 300 mostly wooden houses were destroyed in the blaze in Dukezong in Yunnan province on Saturday.
The town, which dates back 1,300 years, is popular with tourists.
The fire prevention system was installed three years ago and cost 8m yuan ($1.3m; £805,000), the Associated Press news agency quoted the Deqen prefecture fire brigade microblog as saying.
Officials said that more than 2,600 people have lost their homes in the blaze, which raged for nearly 10 hours before it was put out by 2,000 firefighters, police and volunteers. No fatalities were reported.
A store owner surnamed Pan told AP on Monday that they would likely be rebuilding what they had lost.
"Travel is really the only industry here," he said.
The blaze started in a guesthouse and was ruled accidental, according to state media citing local officials. The damage was estimated to be worth 100m yuan, state TV reports.
The county where Dukezong is located has enjoyed an increase in tourist revenue since changing its name to Shangri-La in 2001 after the make-believe Himalayan land of James Hilton's novel.