After 218 days of construction and almost another year of legal wrangling before that, the Brentwood Costco had its grand opening on March 7th, 2025. Completed about a month before that was the Sand Creek extension for CA State route 4 that allows access to the Costco from two exits. The extension will hopefully relieve some of the congestion Lone Tree Way.

The ribbon cutting ceremony took place just moments before the hundreds of shoppers were allowed in the store at 7:38 AM March 7th, 2025.
I have created a short video showing the work from grading the land to grand opening – Costco Brentwood Construction – Grand Opening

Two hundred and fourteen days before the grand opening there was just a large graded hole in the ground where the Costco would be built.
Before construction began, I did some research into how long it took to build a Costco. I saw several people claiming it would take about 100 days because Costco’s were built using tilt-up construction. THAT is WRONG.
I saw every phase of the construction. There was NO tilt up construction. The walls were built with either cinder blocks, or insulation with aluminum siding on it. The only wall that was concrete poured was the loading dock wall.

The shell of the roof has been completed as workers ad insulation.

It turns out the fastest and most effective way to lift multiple cooling units to the roof of a Costco is by helicopter.

The 32 pump gas station opened March 6th, 2025 one day before the Grand Opening. Costco membership is required to purchase gas there.

The line for the alcohol specials started at 10:30 AM Thursday March 6th, twenty-one hours before the Grand opening. By 8:30 PM on the 6th the line had about 30 people in it. At 6:30 AM the day of the grand opening, there were hundreds in the line. The line for regular shoppers started 3.5 hours before the grand opening at 4AM.