The small town, or rather the village, Futaba had about 5,600 inhabitants before the earthquake and meltdown in 2011.
Since then, it has been part of the closed areas, while careful remediation work is underway.
The clean-up costs billions and is not yet complete.
But last year, the authorities approved that people be allowed to move back to Futaba on probation.
Only 15 people applied, and five of these have now arrived to inspect and move into their old neighborhoods.
- It's flowing!
For the first time in ten years and eleven months, tap water comes out of here, says one of the volunteers on Japanese television when he tests the water supply on the site.
Earthquakes, tsunamis, meltdown
The quake had a magnitude of 9.0 and triggered tsunamis that led to a meltdown in Fukushima's nuclear power plant.
This led to new concerns around the world about the dangers of nuclear power.
The quake and tsunami caused more than 18,400 people to lose their lives or be classified as missing.
The radiation from the meltdown meant that large areas in Fukushima prefecture were blocked off for years.
Last year, 2.4 percent of the prefecture still had an access ban.