The 35-year-old woman, identified as Nutan, took the extreme step early on Tuesday owing to marital discord.
She first pushed her minor daughters, aged 3 and 5, and then her son into the small water tank, which was about eight-foot deep, in their house in Badana village of Jhajjar district and later herself jumped into it.
Before that, the woman rang up police and said that she was fed up with her "husband's habits" and was ending the lives of her children and was going to commit suicide.
A case under relevant provisions of the law has been registered in connection with the incident, police said.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.