The lifeless body of Priter Wangui was found in the 50-liter container by the mother moments after she had stepped out and into their house in Shauri village.
Police said they have informed the mother of the child had gone to take a shower on Sunday evening and left her on a sofa set while there was water in a basin.
The child walked there and drowned in the water.
Police were called and took the body to the mortuary.
Police are investigating the tragedy.
Such incidents are common in homes.
Meanwhile, police are investigating the death of a 22-year-old girl whose body was found in her bathroom in Kilimani area, Nairobi.
Kaisy Koch was rushed to Coptic hospital where she was pronounced dead on arrival.
Police said the deceased was in the company of her friends at a house party at Vesta Garden Apartment along Ngong Road
House when she excused herself to go to the bathroom to take a shower.
While in the bathroom her friends who were in the same suit bedroom heard her fall inside.
They called her but there was no response and immediately informed their male friends who were in the sitting room rushed and broke the bathroom door and found her lying down holding the shower pipe on her right hand which also had burn bruises on the first finger and the chest.
Police suspect, she was electrocuted. Investigations are ongoing.
