Meanwhile, many residents in the city of Hammond are reporting flooded basements, left to pump out thousands of gallons of water to the street.
People who live in the neighborhood have a big mess on their hands. Some have 1 foot or more of standing water in their basement hours after the rain finally stopped.
Homeowner John Gorman took ABC7 inside, showing how the water is still coming up through his basement drain.
Heavy rain floods Hammond homes and roads, impacts Whiting BP refinery
"It's still coming up from the storm drains into the basement. There's no sense for me trying to do anything until it stops," Gorman said.
His sump pump is running, but unable to keep up with the water coming in.
"I think it'd be better if your house burns down compared to flooding, because you got to tear everything out and start from scratch," Gorman said.
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A few doors down, Darrell and Yvonne Cates are completely overwhelmed. About 1 foot of water covers every inch of their basement.
"We got a finished basement. Our floors and everything, just floating around. Yeah, real bad down there," Daryl said.
He says the water ruined his furniture, and probably his appliances, including a fridge, freezer, and brand new washer and dryer.
"I come outside, the whole block, everybody's basement are flooded. Yeah, so I got my work cut out for me," Daryl said.
The Hammond Sanitary District reported that sewers and the wastewater plant are operating at full capacity. But with a soaking rain over the weekend, and up to 8 inches more overnight, many residents are left helpless.
"Well, we just got to get the water out the basement, just waiting to hear something from our insurance company," Yvonne said.
Nearby, the BP Whiting Refinery says its operations were impacted by the storms, with the smell of oil thick in some areas.
A stretch of 121st Street, between Schrage Avenue and Front Street, was shut down to traffic because of an oil sheen. The refinery says it is burning materials in the flares to maintain safe operations.
The company released a statement saying, "The Whiting Refinery's operations were impacted by the significant thunderstorms overnight in Northwest Indiana that led to flooding and severe conditions in the surrounding neighborhoods. Response and operations crews are on-site to manage impacts from these storms.
"Materials are being burned in the flares to maintain safe operations. Further, we are aware of reports of odors in the neighboring community and are responding. Due to a sheen on 121st Street in Whiting, the street is closed to traffic and the public between Schrage Ave and Front St. Our crews are also managing this situation.
"Whiting Refinery has detailed weather protection plans in place to handle these types of conditions and have been executing those plans from last night through this morning. Our top priority is the safety of our employees, contractors, and the community and the environment. We will continue to monitor weather conditions closely and are prepared to respond as necessary."
As for people impacted by flooding, the city of Hammond says public works crews will help residents with cleanup by removing items left at the curb or in the alley this Saturday and Sunday.
Storms damage Oswego schools, forcing students to move to e-learning
And over in west suburban Oswego, administrators say at least 11 schools, nearly half of those in the district, have seen water damage from recent rains.
The storms have hit Oswego East High School the hardest, and students there have been doing e-learning over the past two days.
Parts of the building are still drying out after recent downpours left multiple floors damaged and district officials scrambling.
"Just it was unbelievable to see the amount of water in the hallways, you know, some of the damage with the ceiling tiles," said District 308 Assistant Supt. Kristen Campbell.
The damage at Oswego East was discovered Sunday morning after administrators said a third-floor drainpipe failed, allowing water to inundate much of the school.
"Went down stairwells, went through the flooring, in between walls, that type of thing," said Oswego East High School Principal Laura Bankowski.
With restoration crews hard at work, the school's 2,700 students moved to e-learning on Monday and Tuesday.
They are scheduled to return on Wednesday after the school was deemed safe.
"They are monitoring air; they're monitoring, doing moisture mapping to ensure that all the moisture is being removed from the environment," Bankowski said.
And other schools in the district are also seeing problems.
At Oswego High School, water damaged parts of a gym, which could be closed for weeks. At Long Beach Elementary School, one waterlogged section of the school is now unusable.
And at least eight other schools in the district are also experiencing minor leaks and damage.
Administrators said last year, the district began a buildings improvement plan to identify needs.
"We are involved in a long-term masters facilities plan where we're inspecting our buildings to try to look at, depending on the age of the building, what are our next steps," Campbell said.
Though students return in the morning, administrators say the damage here at Oswego East could take several weeks to fully repair.
Weather alerts remain in place
A Beach Hazards Statement remains in effect in Cook County until 10 a.m. Thursday and until 4 a.m. Thursday for northern LaPorte County.
A Flood Warning is in effect until 1 p.m. Wednesday for Lake County, Illinois and Kenosha County, Wisconsin.
A Flood Warning is in effect until 1 a.m. Wednesday for Will County.