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PG&E plans major gas main work between St. Helena and Calistoga

PG&E plans major gas main work between St. Helena and Calistoga

PG&E work in St. Helena, 2015

PG&E work takes place in south St. Helena in 2015. Starting in September, the utility will perform major upgrades and tests along its natural gas pipeline between St. Helena and Calistoga.

PG&E plans to conduct months of strength tests and upgrades to the eight miles of gas pipeline between St. Helena and Calistoga, starting in September.

The transmission pipe dates back to the 1930s and much of it needs to be replaced. PG&E is also facing a capacity issue, with developments coming online throughout the valley that will exceed the capacity of the current system, according to the utility.

Work will happen at night and be “highly impactful due to traffic disruptions and noise,” according to PG&E. Traffic control will be in place at night, but all lanes of traffic will be open during the day, project manager Brian Garber told the St. Helena City Council on Tuesday.

From September 2021 through May 2022, PG&E will replace the pipeline along Highway 29 between Pratt Avenue and Madrigal Family Winery south of Larkmead Lane. Crews will excavate a trench to install the new pipe. In some locations, the pipe will be installed using trench-less methods. Most services to customers north of St. Helena will be replaced.

PG&E will also use horizontal directional drilling to install 1,000 feet of pipe under Sulphur Creek from Main/Mitchell to across the street from Gott’s.

PG&E will use the field across from St. Helena High School as a staging yard.

Other heavily affected areas include Main Street in front of the Sunshine Foods parking lot, Main/Madrona, Main/Elmhurst, and Main/Pratt.

More “highly impactful” work will occur from September through December during strength tests between Gott’s Roadside and Pratt Avenue in St. Helena, and between Madrigal Family Winery and Dunaweal Lane near Calistoga.

The strength tests involve venting and cleaning the pipeline, excavating sections that need to be retrofitted, filling the pipeline with water, and pressurizing the system to levels that far exceed normal operating pressure for eight hours. Any failed sections will be replaced. After a successful test, the pipeline will be dried out and returned to service.

In areas where the pipe is taken out of service, PG&E will use tanker trailers and large bottles of compressed natural gas to supply customers with gas service. On rare occasions, there could be gas outages of typically less than 30 minutes.

PG&E plans to spread the word about the project through letters, phone calls, emails, door-to-door outreach, and possibly community open houses, depending on COVID-19 restrictions.

Businesses and residents should direct questions to Michele Williams at (415) 238-5349 or

Napa County residents will benefit from this Solano County project designed to end Highway 12/Jameson Canyon backups.

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You can reach Jesse Duarte at 967-6803 or

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