Three townships in the city's Yucheng District were flooded, affecting some 16,900 people, China's official Xinhua news agency reported Tuesday.
Downpours also submerged the quake-razed ruins of Beichuan Qiang Autonomous County that received nearly 12 inches of rain.
Three bridges have collapsed since Monday evening in the cities of Jiangyou and Deyang.
Flooding caused a landslide in the village of Shilibei and also cut off telecommunications and access to roads in many townships of Beichuan.
The rainstorm affected inbound and outbound flights at the airport in the provincial capital of Chengdu, stranding some 4,000 passengers.
Economic loss from the flooding has been estimated at $125.18 million.