She was ordered to pay 30,000 yuan (US$4,200) for the damage, about 280 times the room rate of 108 yuan per night, the South China Morning Post reported.
The guest, whose identity was not revealed, had booked the room at a budget hotel in the southern island province of Hainan for a one-night stay.
After checking in late on Oct. 28, she immediately asked for a full refund, claiming a "change of plans," The Star reported.
When the hotel refused, she complained that the room was shabby and badly soundproofed.
The manager said staff offered her a free upgrade, which she declined.
She then contacted the police and a local government hotline to lodge a complaint.
While waiting for officers to arrive, the woman turned on the bathroom sink and shower, deliberately flooding the room.
Staff discovered the damage only when water began leaking from her second-floor room into the lobby below.
The taps reportedly ran from about 2 a.m. until sunrise, causing severe damage to the walls and floor.
The hotel estimated repair costs at about 20,000 yuan.
Under Chinese law, intentionally damaging private property can bring fines or detention, and damage exceeding 5,000 yuan may lead to criminal charges.
The incident drew widespread attention online.
"She ended up paying nearly 300 times the hotel room rate she wanted to avoid," one user wrote.
Another added: "Anger can cause great consequences if we do not put a leash on it. The law can be a good leash."