Local governments in western Japan say that as of 10:30 AM on Wednesday, more than 7,200 people are taking shelter at municipal evacuation centers in 15 prefectures.
Okayama Prefecture has the largest number of evacuees at 3,050, and Hiroshima Prefecture has 2,996.
Health ministry officials say more than 255,000 households were without water as of 8:00 PM on Tuesday.
Telecom company NTT West says 15,900 landline and internet connections are down over a wide area of western Japan as of Wednesday.
Mobile phone companies say the heavy rain has damaged communications cables and other infrastructure, disrupting a wide range of services.
They say they are sending mobile base stations to the affected areas and repairing equipment as quickly as possible.