PWD Minister Satyendar Jain visited the site amid protests by locals and later ordered a magisterial probe.
The South Delhi Municipal Corporation, under whose jurisdiction the area falls, said the Delhi Jal Board was executing certain works in the colony.
The deceased were identified as Manju (26), Daksh (5) and Tannu (2). Husband of the deceased Sushil, 28, sustained injuries and was admitted to hospital, police said.
Delhi BJP chief Satish Upadhyay met the affected family and demanded registration of cases against Water Minister Kapil Mishra, who is also the chairman of DJB, and local AAP MLA Naresh Balyan over the deaths.
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Congress leader Mukesh Sharma, who visited the spot as well, blamed the BJP-ruled MCD as well as PWD and DJB for the incident and demanded a case of "murder" registered against the agencies concerned and compensation for the family.
"This is ridiculous. Minister Jain has already visited the spot and ordered a magisterial probe. It will bring out the truth," Mishra said.
SDMC also ordered an inquiry by its Building Department while adding it was only responsible for cleaning small drains in the colony.
"The two-storey house being a temporary structure was covered by tin iron roof; the ground floor was being used for the cattle whereas a family was putting up at first floor of the house.