County engineers recommend replacing water-tank roof; temporary repairs expected to hold a year or two

The Carroll County Commission heard a detailed evaluation of options for the countys aging water-storage tank on April 6, with a consulting engineer recommending replacement of the tanks plank roof and warning that temporary repairs were only a short-term fix.

Lynette of Underwood Engineer summarized the firms review and said engineers had stabilized cracked concrete planks last fall but that the fixes were intended to buy time. "The intent was to give you a year or two kind of thing to be able to pull the funding together to fully address the problem," she said.

Underwood presented three broad options: replace the existing concrete-plank roof with a like-for-like solution; build a peaked wood or metal roof (which the consultants argued would require heavy maintenance and frequent repainting because of the wet tank environment); or erect an aluminum/fiberglass panel cover system (sometimes used on wastewater tanks). The firm said lifecycle costs for the aluminum "cowall"-type systems were similar to plank replacement, and noted such covers can admit light and thereby encourage algae growth that makes maintaining a chlorine residual more difficult.

The engineer told the board that interior inspections in 2018 and in late 2025 showed no obvious tank structural problems and that panels were mostly in good shape, but that the current premature plank failures likely stemmed from how the planks were originally clipped around the tank perimeter, restricting expansion and contraction. Underwood recommended a replacement approach that allows one end of planks to move, similar to modern bridge expansion details, to avoid recurrence.

Commissioners asked about alternatives to full replacement, including installing a divider wall to create two bays and allow half the tank to be taken offline for cleaning and maintenance. Underwood said a divider would add piping and new inlet/outlet connections but would increase operational flexibility. The consultant also noted that constructing a second standalone tank of similar size would be far more expensive and could create problems with water age in a system that already has substantial storage.

No final design contract or construction authorization was approved at the meeting. Commissioners signaled they will discuss a formal design phase and updated cost estimates as the next step; staff said a 30% design would produce a more refined cost that could be adjusted later.