Linn County approves RFP for countywide water-resources study as data-center interest grows

The Linn County Board of Supervisors on Oct. 6 authorized release of a request for proposals for a countywide water-resources and water-balance study after supervisors said growing interest from large data centers and other water‑intensive industries makes a baseline assessment urgent.

Supervisor Rainmore (as identified in the meeting transcript) opened the discussion by linking three major proposals now under consideration — data centers, a proposed natural‑gas power plant, and potential ethanol facilities — and said the county needs data before major development proceeds. “Google has agreed to pay for this study, and we will share the information when we get it,” Rainmore said during his remarks.

County sustainability staff framed the RFP as a technical, multi‑phase effort. Kara Mattson, the county’s sustainability director and hydrologist, told the board the study would first compile and evaluate existing data, then collect additional monitoring information as needed, and finally produce models and real‑time monitoring recommendations to inform long‑term water management. She said the RFP will ask consultants to propose work at three scales: a focused priority area, an intermediate (township) area and the whole county to establish a countywide baseline.

Darren Gage, director of policy and administration, described the logistics: staff plan to give consultants three weeks to prepare proposals and encourage collaborative teams to bid because the scope is technical and multidisciplinary. Gage said the RFP is atypical but necessary given the scale and potential regional consequences of the projects under review.

Supervisors stressed two priorities: protect residential water supplies and make planning transparent. Rainmore noted several technical but unresolved questions about aquifer–surface water interactions in Linn County and argued those unknowns justify the study. “Water is a part of our critical infrastructure, and we want to take into consideration where data centers would be getting their water from, how much they would need,” he said.

The board voted to approve release of the RFP and asked staff to return future contracts for formal approval. The motion passed with an affirmative voice vote.

Context and next steps

In the meeting staff said the RFP would evaluate existing monitoring, identify data gaps, and recommend additional monitoring or modeling to detect interactions between the county’s rivers and principal aquifers (alluvium, buried channel deposits, Silurian, Devonian/fractured bedrock and Jordan sandstone). Mattson said the scope also calls for a policy review and recommendations drawn from best practices nationwide.

Staff told supervisors that Google and another data‑center inquirer had asked about locating in unincorporated Linn County; Rainmore said Google had discussed locating a multi‑building campus near the Duane Arnold site. The meeting transcript includes an estimate attributed to Rainmore about typical six‑building data‑center water use; the exact figure as read aloud in the meeting was unclear in the record. Staff emphasized that residential water supplies are the county’s priority and that the study is intended to create an objective baseline to guide permitting, zoning, annexation decisions and potential host‑community agreements.

Related University of Iowa contract

Separately at the same meeting the board authorized the chair to sign a contract with the University of Iowa for related groundwater studies that will support Linn County’s comprehensive water‑quality management and mitigation plan. Kara Mattson said the contract (10/01/2025 through 09/30/2026) comprises three projects: an aquifer vulnerability map for the county, mapping and modeling of known contaminant plumes, and a countywide surface‑water sampling and monitoring program. The contract amount was described in the meeting as not to exceed $130,000; the board voted to authorize the chair to sign.

Why it matters

Supervisors and staff said Linn County lacks a consolidated, countywide baseline of groundwater and surface‑water availability and that major new loads of consumption could have long‑term effects on municipal and rural wells, ecosystems and neighboring jurisdictions. Several supervisors urged transparency and regional coordination (including with the city of Cedar Rapids), and staff said the study is designed to provide actionable data and policy recommendations for the county and partner jurisdictions.

What the study will not do immediately

Board members emphasized the study itself does not approve or disapprove any development. It is a data and planning exercise meant to inform future ordinance language, host community agreements, and permit conditions. Staff said any specific agreements, contracts or zoning decisions would return to the board for separate votes.

The board approved release of the RFP and authorization of the University of Iowa contract during the Oct. 6 meeting; staff said further contract documents and technical scope details will be presented to the board as those items are finalized.