East Lyme — A proposal for a Costco big-box store near Interstate 95's Exit 74 cleared its final municipal hurdle Tuesday night,  allowing developers to potentially break ground in early 2019.

The Water and Sewer Commission voted 8-1 to approve a 7,650-gallon daily sewage capacity for the more than 158,000-square-foot store.

The store would serve as the initial phase of the retail component proposed for the Gateway Commons development, a 200-acre site between Exits 73 and 74. Gateway developers have built 280 apartments near Exit 73 as part of that development, and recently proposed an additional 120 rental units to be built over upcoming years.

Before approving the sewage capacity Tuesday, town officials expressed caution about tapping into the town’s finite sewage capacity and questioned how to properly allocate that capacity moving forward — especially with other residential and commercial developments associated with the Gateway Commons in the pipeline.

Costco’s proposal, however, would use a “modest” percentage of the town’s remaining capacity — approximately 3 percent of an estimated 262,000 gallons still available daily. As contracted with the city of New London, East Lyme is allowed up to 1.5 million gallons of sewage per day, all of which is sent to New London's treatment plant.

“Costco’s application is a small amount. It’s the future developments that we are trying anticipate,” said Municipal Utility Engineer Bradford Kargl before Tuesday’s meeting. “There are a lot of other projects coming through, and all of that will have a significant impact on the scope of what’s available. We are trying to gauge how to best approach that.”

Tuesday’s final approval comes years after initial negotiations for the development began between the town and The Simon Konover Co. of West Hartford, which is developing the Gateway site with KGI Properties of Providence. The zoning commission first approved their master development plan in 2008.

Last month, the Costco proposal still needed town approval for a building permit, as well as other permits from the state Department of Transportation and Office of the State Traffic Administration.

Building Official Steve Way said Tuesday he reviewed the developer’s application and expects to sign off on it in coming weeks, saying that Tuesday’s sewage capacity approval was the last major hurdle the development needed on the municipal level. The approval was needed for Way to approve the application.

Developers still need a final go-ahead from the town’s fire marshal on their building permit application. That approval is also expected to happen in coming weeks, Way said.

“Once that happens, they will have the building permit,” Way said.

“We want to get them digging, clearing and doing what they need to do on the site before it gets much colder,” Way said, adding that building construction will likely begin in spring. “They’ve done enough of these, it’s cookie cutter for them once they get going. But if they can get in the ground before the frost, they’ll be able to move forward on schedule.”

m.biekert@theday.com