Illinois data center compliance guide: federal, state and local requirements

Soils and old mines

Foundation design for heavy equipment rooms depends on site-specific soils, and parts of central and southern Illinois sit over old underground coal mines. The ISGS coal mine viewer shows where, but it isn’t meant for site-specific decisions.

You'll need: geotechnical borings and early testing to confirm bearing capacity and any subsidence risk

• ATSMaterials testing→

Environmental history

Lenders and buyers will expect a Phase I environmental site assessment before acquisition, and a Phase II if it flags concerns. On former industrial land, an Illinois EPA No Further Remediation letter is the record buyers look for.

You'll need: an ASTM-based Phase I in the diligence file

• SGSEnvironmental site assessments→ (opens in a new tab)

Home rule and local pauses

Inside a municipality, its adopted building code and special inspection program apply, and many Illinois towns are home rule. Plainfield, West Chicago, Lake County and Champaign County, among others, paused data center approvals in 2026.

You'll need: confirmation of local moratorium status and a decision on who will act as your independent inspection and testing agency

• ATSInspection services→

Protected species and natural areas

State agencies and local governments must consult IDNR, usually through EcoCAT, before approving actions near state-listed species or natural areas. Illinois EPA also asks for the EcoCAT and SHPO letters with your stormwater filing.

You'll need: EcoCAT and SHPO letters early in due diligence

Special inspections

Municipalities and counties that adopt the International Building Code require third-party special inspections of structural concrete, steel, welding and fireproofing.

You'll need: an approved special inspection agency and daily reports the building official will accept

• ATSInspection services→
• ATSConcrete testing→

Welds and structural connections

Structural steel, pipe supports and generator skids need weld inspection and nondestructive testing before they’re covered up.

• ATSNDT services→

Construction stormwater

Disturbing an acre or more needs coverage under Illinois EPA’s NPDES general permit for construction, filed with a SWPPP, and inspectors check BMPs in the field.

You'll need: documented inspections throughout the build

Generators and fuel

At FESOP or CAAPP sources, SB 25 requires air permit applications filed from Dec. 1, 2026 to propose Tier 4-level diesel generators. Fuel tanks bring Office of the State Fire Marshal rules and a federal SPCC plan.

You'll need: generator specifications, emission controls and tank documentation ready to file

• ATSGenerator services→

Commissioning before energization

ComEd’s large-load tariff ties larger deposits and service agreements to your requested load, so a failed integrated test can cost you money and your place in line.

You'll need: commissioning records and integrated systems test results showing the systems perform as designed

• ATSCommissioning support→

Electrical maintenance

NFPA 70B is now an enforceable standard with required maintenance intervals and condition assessments for electrical equipment. Insurers and AHJs increasingly ask for the records.

• ATSElectrical infrared thermography→
• ATSCondition monitoring→

Backup power readiness

NFPA 110 calls for regular generator exercise and load testing. Illinois air rules limit emergency units to emergency and standby use plus testing, so your run-hour logs need to match your permit.

• ATSGenerator services→

Cooling and mechanical reliability

Pumps, chillers and CRAH fans fail gradually, and the warning signs show up in vibration data first.

• ATSPredictive maintenance→
• ATSPump vibration analysis→

Monitoring you can trust

Environmental and power sensors drive alarms, PUE and the energy and water figures the pending POWER Act and Chicago’s proposals would have you report. Uncalibrated sensors produce numbers you can’t defend.

• ATSSensor calibration→
• ATSCalibration services→

Tank closure

Underground fuel tanks come out under an Office of the State Fire Marshal removal permit, followed by a site assessment for releases and a notice to OSFM that removal is complete.

You'll need: inspection and sampling before the tanks come out

Batteries and hazardous materials

UPS and battery energy storage systems need proper removal, handling and recycling records, as do any EPCRA-reportable chemicals on site.

Exit assessment

A post-operations environmental assessment protects the seller and the next owner. If it finds a problem, Illinois EPA’s voluntary Site Remediation Program can end with a recorded No Further Remediation letter.

• SGSEnvironmental site assessments→ (opens in a new tab)
• SGSTechnical due diligence→ (opens in a new tab)