735 ILCS 30/10-5-50
Evidence is admissible as to: (1) any benefit to the landowner that will result from the public improvement for which the eminent domain proceedings were instituted; (2) any unsafe, unsanitary, substandard, or other illegal condition, use, or occupancy of the property, including any violation of any environmental law or regulation; (3) the effect of such condition on income from or the fair market value of the property; and (4) the reasonable cost of causing the property to be placed in a legal condition, use, or occupancy, including compliance with environmental laws and regulations. Such evidence is admissible notwithstanding the absence of any official action taken to require the correction or abatement of the such illegal condition, use, or occupancy.
735 ILCS 30/10-5-50