Mold likes warm places with a lot of moisture. Due to its climate, Illinois is under attack from the mold during a larger part of the year. There are many properties, both rental and non-rental that have to struggle with this issue, especially basements or attics. If you are looking to rent a place in Illinois you need to know everything you can about renter rights and mold in IL. There are not direct law stating how and what a landlord needs to do about mold in the place he is renting. That holds true for both state and federal laws. But they are required under law to keep the premises safe for tenants to live in. This is what makes the mold and renting tricky since it is in a sort of legal gray zone.
In Illinois, the court can’t order a landlord to clean mold, but it can hold them accountable if they neglect their property so much that the tenants start experiencing health issues. There have been a number of cases where tenants have gone to court with their landlords to seek reparations for all the damage and health issues that they suffered because of their neglect to adequately rid the property of mold. A higher profile case even got awarded a bigger amount of money, around 25 thousand dollars. The law is also in favor of landlords when it comes to declaring potential mold problems. If they are looking to see or rent a place, they do not need to tell the people they are selling or renting what kind of mol issues the place had in the past. The federal law holds the same maxim. The only thing landlords have to declare is the presence of radioactive material.

The state does its inspections to see if there are any surface problems with the property. But, if the walls have been deeply infested with mold or something similar, it is easy for landlords to hide them, and for the inspectors not to notice. But as a tenant, you are not without right. If you started to rent a place and right away discovered that it has mold, you can write a request for the landlord to deal with this issue. The landlord has time from 15 to 30 days to repair. If he does not comply, the tenant can look for help in courts. Sometimes it is also possible to get out of the lease if the landlord doesn’t cooperate.
https://www.nolo.com/legal-encyclopedia/illinois-rules-regarding-mold-rental-properties.html