County delays major geothermal equipment purchase after reviews show uncertain well flow and fine‑sediment problems

Okanogan County commissioners on Tuesday paused a planned purchase of nearly half a million dollars in geothermal equipment for the courthouse and jail after county staff and outside consultants told the board they lack key data about the system's ability to return groundwater and about fine sediment that has been clogging heat exchangers.

The issue matters because the geothermal system is the county's primary cooling source for the jail and a malfunctioning system contributed to repeated high indoor temperatures. Contractors and maintenance staff told commissioners the system has run nonstop, that some heat‑exchanger components have already failed, and that the county cannot be confident new equipment will work until it knows how much water the return/injection wells will accept and how to filter fine sediment from the water.

Maintenance staff and Devco consultant Chad Alverson reviewed the county's operational history of the system and told the board the project faces two linked technical problems: limited return capacity at the injection wells (historically measured only by pressure, not flow) and very fine sediment that plugs the small internal passages in heat exchangers. Staff said those conditions led to repeated tripping and cracked exchangers, requiring component replacements and frequent resets.

County staff described current stopgap arrangements: a temporary rental cooling unit that has been in place for multiple years, and an ad‑hoc practice of spraying the temporary condenser to lower coil temperatures on very hot days. Commissioners and staff reported substantial rental costs and expressed concern about continuing to pay for temporary units while also authorizing a large capital purchase. One staff estimate in the meeting placed the vendor's proposed equipment cost “near $480,000,” and staff said lead times for new units could be months.

After extended technical discussion, commissioners gave three near‑term directions: (1) do not authorize the proposed large equipment purchase until the county can document well return capacity and address sediment issues; (2) install a calibrated flow meter on the return/injection piping to measure gallons‑per‑minute and determine the maximum safe return volume; and (3) work to negotiate credits or replacement with the rental vendor (Sunbelt) for the existing temporary unit and, if necessary, secure a replacement temporary unit to protect jail operations this summer. Commissioners also asked staff to consult Oroville School District and other local users about their filtration/maintenance fixes.

Staff and the Devco consultant recommended addressing the technical priority questions before proceeding with design or ordering of new geothermal heat‑pump equipment. They flagged additional concerns: exposed plastic injection piping and limited access to some mechanical spaces that reduce reliability, and the absence of historical flow measurements that would allow engineers to size replacement equipment with confidence.

Next steps recorded at the meeting: staff will (a) order and install a flow meter on the injection/return line, (b) ask the county's mechanical engineer and the vendor to propose filtration options for very fine sediment, (c) pursue credit or replacement negotiations with the temporary‑unit vendor, and (d) return to the board with measured flow data and recommended technical options before any large equipment purchase.

Commissioners emphasized they wanted a plan that prioritizes reliable cooling for the jail this summer and avoids committing capital funds until the technical limits of the existing wells are measured and addressed.