Three other people were seriously injured including an 11-year-old boy and a 54-year-old woman.
Southern Gas Networks (SGN) declared the area safe on Tuesday.
An SGN spokesman said: “Our engineering teams have now completed work in Galpin’s Road, Thornton Heath, to disconnect a section of our gas network in support of the ongoing police investigation.
“Residents will start to return home tomorrow in an operation managed by Merton Council, however this will take time due to the need to complete safety checks on all properties.”
Merton Council said that almost all residents, most of whom have been staying in hotels for more than a week, would be returning from Wednesday, with the exception of those from a handful of houses closest to the blast.
House number 255 was completely destroyed by the explosion, while two neighbouring terraced homes suffered extensive damage and several more had smashed windows.
SGN previously donated £500,000 to help the council support affected neighbours.
At a community meeting last week attended by an SGN representative, angry residents accused the firm of having “blood on their hands” and said they made at least 18 calls reporting gas smells in the days before the explosion.