Gas main extensions for new development follow a process parallel to electric service extensions, governed by PG&E's Rule 15 (Gas Main Extensions). The developer advances the cost, PG&E designs and constructs the extension, and a revenue credit mechanism refunds a portion of the advance over time. But the gas landscape is changing. Many jurisdictions now prohibit or discourage natural gas in new construction, making the question of whether to extend gas service at all increasingly relevant.

Rule 15: Gas Main Extensions

Rule 15 is the tariff that governs PG&E gas distribution main extensions to new customers. The structure mirrors Rule 16 for electric:

  1. Developer requests service — submits a project inquiry with the gas demand estimate (peak therms per hour for each building and service point).
  2. PG&E provides a cost estimate — typically within 4 to 8 weeks for standard residential and commercial projects.
  3. Developer pays the advance — the estimated cost of the main extension, service laterals, meters, and regulators.
  4. PG&E designs and constructs — installs the gas main, service lines, meters, and regulators.
  5. Revenue credits — PG&E refunds a portion of the advance as new customers begin gas service. The refund period is typically 3 to 5 years.

What the Developer Installs vs. PG&E

Unlike electric service (where the developer installs conduit and vaults), gas main construction is almost entirely PG&E's responsibility. The developer provides:

  • Trench and backfill — in some cases, the developer digs the trench for the gas main to PG&E's specifications, PG&E installs the pipe, and the developer backfills. In other cases, PG&E handles the entire operation.
  • Meter locations — the developer must provide adequate space for gas meters at each building, per PG&E specifications (minimum clearances, accessibility, protection from vehicle damage).
  • Stub-outs — the plumber installs the building gas piping from the meter to the appliances. PG&E is responsible for the piping from the main to the meter.

Timeline

Gas service extensions are generally faster than electric because the equipment is simpler (no transformers, no switchgear) and the construction is more straightforward (welded PE pipe versus cable pull in conduit):

StepDuration
Project inquiry and cost estimate4-8 weeks
Agreement execution and advance payment2-4 weeks
Design4-8 weeks
Construction (main extension)2-6 weeks
Service line installation and meter set1-3 weeks
Total13-29 weeks (3-7 months)

This is faster than electric, but it still requires planning. Do not assume gas service will be available by the time you need it without initiating the process early.

Cost

Gas main extension costs depend on the length of the extension, the pipe diameter, and the surface restoration requirements:

  • Main extension in open trench (new development): $30 to $60 per linear foot for a 2-inch PE main; $50 to $100 per linear foot for a 4-inch PE main.
  • Main extension under existing pavement: $80 to $200 per linear foot including pavement cuts, traffic control, and restoration.
  • Service laterals: $2,000 to $5,000 per service connection, including the meter and regulator.

For a typical 20-lot subdivision requiring a 2-inch gas main extension of 1,000 feet plus 20 service laterals, the advance payment would be approximately $70,000 to $160,000.

The All-Electric Question

An increasing number of jurisdictions have enacted reach codes or building electrification ordinances that prohibit or discourage natural gas in new construction:

  • California's 2022 Building Energy Efficiency Standards strongly incentivize all-electric construction through the performance compliance pathway.
  • Cities including San Jose, San Francisco, Oakland, Berkeley, and others have enacted local ordinances that prohibit gas piping in new construction (though some include exemptions for commercial kitchens and specific industrial processes).
  • Oregon has not enacted statewide gas prohibitions, but Portland and other cities are considering electrification mandates.

For projects in jurisdictions with electrification mandates, the gas main extension question is moot — there is no gas service. For projects in jurisdictions without mandates, the decision involves weighing the gas extension cost against the cost of all-electric building systems (heat pump HVAC, heat pump water heaters, induction cooking), the ongoing gas utility bills, and the long-term trend toward electrification.

Practical advice: Even if your project is in a jurisdiction that still allows gas, consider whether the gas main extension cost ($70,000+ for a subdivision) could be redirected to electrical panel upgrades and heat pump equipment that eliminate the gas utility entirely. The capital cost comparison is often closer than people assume, and the operating cost of heat pumps is typically lower than gas furnaces and water heaters at current energy prices.

Coordination with Other Utilities

Gas mains are typically installed in the same trench as other dry utilities (the joint trench) or in the street right-of-way. Minimum separations from other utilities must be maintained:

  • 12 inches from electric conduit (with a separation barrier)
  • 12 inches from water mains
  • 6 inches from communications conduit
  • 12 inches from sewer laterals

The civil engineer shows the gas main on the utility plan and joint trench cross-section. PG&E reviews the plans during the plan check process and provides comments on alignment, depth, and separation. Resolve these comments before construction — field changes to gas main routing are slow and expensive because PG&E must approve any deviation from the approved plan.