The victims say the water was purchased at Ultra Foods in Chicago Heights. Officials at the store say they are now sending a sample of the product out for testing.
It was unclear Sunday night if the women, who remained hospitalized, were sickened after drinking tainted bottled water or if something else was the cause.
"I thought I was going to die. I thought I was dead," Vera Gardner told ABC7 Chicago.
Still in guarded condition, Gardner talked Sunday about the bottled drinking water she said made her, a cousin and her older sister seriously ill. She says it happened at a surprise birthday party for relatives.
"My mouth was burning. My lip, I mean tongue, the top of my mouth was burning. I mean, straight on through here," said Margie Beatty. "It was like a choking sensation."
Beatty drank the water, too, along with their cousin, Crystal. Family members and health authorities say they are trying to figure out what happened.
"They [doctors] were unable to go in because of the redness and swelling," said Jimmy Beatty, who attended the party. "So, no, they have not been able to ascertain exactly what's going on."
Jimmy Beatty, a suburban police officer, says the event was held in a room rented at a church. The evening was catered by his cousin, who is a culinary student. The party's organizer, another relative, reportedly bought the water, eight, one-gallon jugs at the Chicago Heights grocery store.
Martha Patterson says although others at the celebration consumed some of the water without any problems, all three who say they became ill felt symptoms instantly and simultaneously after taking only a few sips.
After the incident, she sampled the water herself.
"I put my finger in there and touched my tongue like that, and it became on fire. The tip of my tongue was on fire, and it took about a half-hour for that to dissipate," Patterson said.
The water in question is called Crystal Lake Drinking Water and is distributed by Pleasant View.
In a statement Ultra Foods said:
"For the safety of our customers, the water will be removed from all our stores. It is from an outside vendor."
Meanwhile, Vera Gardner says she just hopes to be better soon.
"It was terrible. There was some type of chemical in that water. It was the worst," Gardner said.
It was unclear when results would be completed on the water sample. However, authorities also are looking into the possibility that the pitcher the water was served from could have been tainted, or some other explanation for the illnesses.