Japan issues weather warnings early, but its dense population means that nearly every bit of usable land, including some flood plains, is built on in the mostly mountainous country, leaving it prone to disasters.
Water and other relief supplies were scarce in some of the other disaster-hit areas.
Torrential rains unleashed floods and landslides in western Japan last week, killing 127 and prompting Prime Minister Shinzo Abe to cancel an overseas trip to cope with the disaster, which at one point forced several million from their homes.
Chief Cabinet Secretary Yoshihide Suga said search operations were continuing after the worst weather-related disaster in Japan in over three decades.
"We've never experienced this kind of rain before", a weather official told the BBC.
"The area became an ocean", 82-year-old resident Nobue Kakumoto told AFP Sunday, surveying the scene.
Construction worker Fukuyoshi Doi, who is leading a group of volunteers who had gathered to help clear the road, said once they clear the mud "the rest of the work would pick".
The water has been cut off in these areas mainly due to damage to water pipes and flooded water purification plants as a result of the heavy rains. Supermarkets have closed stores or shortened hours due to delivery delays and supply shortages.
More than 200,000 households had no water a week after disaster struck and many thousands of people were homeless.
On Wednesday, residents lined up for water under a scorching sun as temperatures rose to 35 Celsius, raising the risk of heat stroke.
At one point during the flooding, evacuation orders were given for almost 6 million people across 19 prefectures. "We need our water system restored". People who have evacuated their homes have since returned and started cleanup.
In the town of Kumano in Hiroshima prefecture, rescue workers were still digging through the dirt of a landslide that enveloped homes over the weekend, crushing some into little more than scrap wood.
In Hiroshima Prefecture, a tunnel that draws water from a river in the city of Hiroshima to pass it to Kure was blocked with earth and sand, halting the water supply to Kure and other areas.
The Transport Ministry, West Japan Railway Co. and local operators of the 27 lines in the affected areas, reported damage at over 100 locations and will be unable to restart services within the next few days.
"I saw the tremendous scars (left by the rain)", Abe said following his visit to Okayama Prefecture on Wednesday during a task force meeting, while revealing that the government has secured about 71,000 dwellings as temporary housing for people affected by the disaster. But for now, the government is focusing on working closely with local counterparts in an effort to save lives.
According to the Japan Meteorological Agency (JMA), an active seasonal rain front caused torrential rain in most eastern and western regions of Japan since last Thursday.