Lake Forest and Lake Bluff residents who pay Lake County property taxes could see a windfall from 25 miles away. Grayslake Mayor Elizabeth Davies projects the T5 Data Centers campus will send $6 million a year to Lake County government and $3 million to the College of Lake County (CLC) at full build-out, the Chicago Tribune reported.

Both Lake County and CLC levy property taxes on homes in Lake Forest and Lake Bluff. Davies said the project would deliver $100 million annually to local taxing bodies overall, with about $1.75 million going to the Forest Preserves and the rest split among school districts and the township.

Opponents say the projections are unverifiable.

Those figures arrived alongside a T5-commissioned economic impact study by Greener Impacts, an Illinois firm led by Sandy Dall'Erba, a University of Illinois Urbana-Champaign professor. The study claims the 472-acre campus along Peterson Road west of Route 83 will generate nearly $10 billion in economic output across Illinois between 2024 and 2031, with $7.27 billion in Lake County.

The study projects $1.45 billion in statewide tax revenue through 2031 and $952 million in combined fiscal revenues for Lake County. During Phase 2 construction, the project would support an average of 13,100 jobs per year statewide. Ongoing operations would support 940 full-time-equivalent jobs in Lake County on average per year starting in 2027, the analysis said.

T5 could not provide a yearly breakdown of local jobs. Critics have argued many positions would be temporary construction work.

Grayslake stands to double its property tax haul

Davies said the village's own analysis projects $5 million a year in property taxes at full build-out, more than doubling Grayslake's current take. Village documents from 2024 put total property tax revenue at about $4.5 million.

Davies repeatedly emphasized the projections rest on factors that could shift. The earliest property taxes from the development likely will not arrive until 2028, she said.

Opponents challenge the math

Bob Landolfi, a member of the Lake County Data Center Opposition Coalition, questioned the assumptions behind the projections. He called for publication of the full Greener Impacts study, including its methods and model inputs.

Landolfi criticized the study's release to reporters before the public, arguing the move avoids being "checked by the people it's meant to persuade." He expressed distrust of any analysis coming from the village or T5.

The coalition supports a lawsuit filed by Preservation of Community Well-Being Collective LLC and nine residents challenging the project’s approvals, including alleged Open Meetings Act violations. Grayslake has moved to dismiss the suit.

Power and water concerns persist

The planned campus could eventually consume up to 1.2 gigawatts of power, enough to power a city of about one million residents, NBC 5 reported. T5 CEO Peter Marin told NBC 5 the facility will operate on a closed-loop cooling system that relies more on power than water.

The Central Lake County Joint Action Water Agency (CLCJAWA) has said T5's design team indicated total campus water use would be less than 50,000 gallons per day, a 0.25% increase in the agency's daily pumpage, according to CLCJAWA's website.

Davies said residents would not see electricity rate increases because of the Grayslake facility. Landolfi called that position irresponsible.

The Lake County Board approved an eight-month moratorium on data centers in unincorporated areas Sept. 8, following recommendations from the Zoning Board of Appeals and the county’s Planning, Building, Zoning and Environment Committee. The moratorium does not apply to T5’s campus within Grayslake.