SMITHFIELD —To blanket the county in broadband access, Johnston might have to settle for second best.

That’s an early takeaway from an inventory of broadband availability in Johnston.

Fiber is best because of the quality of the connection, but it’s also expensive, Jeffrey Brooks of consulting firm ECC Technologies told Johnston County commissioners recently. “Probably $40,000 to $60,000 a mile to build fiber,” he said.

An alternative is to place an antenna on a cellphone or water tower, said Brooks, whose firm is conducting the broadband inventory. “To deploy wireless, to go up on a tower that’s already existing, you might think in terms of $3,000, $5,000, $10,000 to be on a tower,” he said. “And then probably $1,000 to $2,000 a month to rent that space.”

In Johnston’s developing communities, fiber is increasingly available, Brooks told commissioners. “In areas out Highway 42 and more in the northwestern parts of the county, there’s a lot of fiber that’s going into residential areas,” he said. “We’re seeing developers build subdivisions, and they’re actually putting in the infrastructure for fiber.”

For a broadband provider — a cable-TV company or phone company, for example — fiber is economically feasible in a densely populated area because the provider will have enough customers to recoup the cost of laying the fiber.

But not every Johnstonian lives in a subdivision, Brooks noted, and because of that, broadband companies can’t afford to lay fiber to their homes. “You may have a house every three or four miles, or a house is two miles down a dirt road,” he said.

No broadband provider is going to provide service to such places without some financial help, Brooks said. “It’s very difficult to get service without grant funding,” he said.

But putting antennas on towers could work, Brooks said. “Wireless represents a potential solution to some of these issues,” he said. “It’s not as good as fiber, but sometimes a hybrid solution is cost-effective and represents a stepping stone to get to where you want to get to in the county.”

When Brooks spoke to commissioners, his company was nearing the end of its inventory of Johnston’s broadband assets, both existing cable in the ground and potential assets like water towers and cell towers. He said his company’s goal was to help Johnston do two things.

“No. 1, make determinations on the best path to expand broadband within the county,” Brooks said. “And No. 2, to maybe have the upper hand, or at least be on an even playing field, in terms of recruiting service providers to come and serve the county, especially in those areas that underserved and unserved.”