Carrier of Last Resort (COLR)

What is a Carrier of Last Resort (COLR)?

 A Carrier of Last Resort (COLR) is a telephone company required to provide basic telephone service to any customer who requests it within a specific area. California has 16 COLRs . AT&T is the largest, followed by Frontier.

The California Public Utilities Commission (CPUC) is taking a fresh look at its COLR rules to keep pace with rapidly changing technology and how Californians use phone services today. The rulemaking addresses key questions: What counts as “basic service”? Which companies should the Commission require to provide “basic service”? And when and how can the Commission relieve a carrier of its COLR obligations?

Why the CPUC Is Reviewing the COLR Rules

In June 2024, the CPUC opened a formal rulemaking (R.24-06-012) to review and update the COLR rules. It did so in part because AT&T had applied to withdraw from its COLR obligations , a move that could have left approximately 29.5 million Californians, including more than 500,000 landline customers, without guaranteed phone service.¹ That application was rejected, and the rulemaking now offers a broader opportunity to update the rules in ways that benefit customers.

The Public Advocates Office has been involved in this proceeding from the start and originally opposed AT&T’s push to drop its landline responsibilities. We now view the process as an opportunity to upgrade communications services for all Californians and modernize them to meet the communications needs of the 21st-century consumer . Regardless of any official change in status, we believe a Carrier of Last Resort must never abandon its customers.

Our Work on Carrier of Last Resort Rules

All Californians deserve reliable, high-quality, and affordable communications services as networks and technologies evolve. The Public Advocates Office has urged the CPUC to:

• Modernize the definition of “basic service.” Update COLR rules to reflect new technologies and expand the basic service definition to include broadband and Voice over Internet Protocol (VoIP) services.
• Require reliability and resiliency. COLR carriers must meet reliability and resiliency standards.² Broadband networks should remain operational during the failure of network segments by building redundant infrastructure and ensuring that multiple providers serve high-risk areas, a critical safeguard for public safety and emergency response, particularly during wildfires.
• Confirm service before releasing a carrier. Before the CPUC permits a COLR to relinquish its obligations in a geographical area, the CPUC must confirm the area already has ubiquitous, reliable, high-quality, and affordable service, so no customer is left behind.
• Update the California High Cost Fund-B . The fund should cover standalone broadband subsidies, helping providers build out infrastructure and keep service affordable in expensive-to-serve areas. This may require more public funding, and reforms must help customers, not subsidize provider profits.

Where the Proceeding Stands

In December 2025, the CPUC issued a Staff Proposal for changes to the COLR rules and asked parties to comment. Under the Staff Proposal, the pathway available to COLR relief depends on whether its service area has Significant or Limited Consumer Choice. The table below summarizes both options.

The Public Advocates Office largely supports the Staff Proposal. The CPUC should offer a faster path to COLR relief for providers that commit to deploying fiber. Fiber provides symmetrical upload and download speeds, can scale to multi-gig capacity, and is “future-proof,” going beyond today’s 100/20 Mbps standard to keep up with increasing demand.

Because COLR rules are technology-neutral, the CPUC must verify that any substitute technology meets modern essential service standards. This means confirming minimum speeds of 100/20 Mbps and setting performance metrics for reliable voice and wireless service.

Key Issues Still to Be Decided

The CPUC must decide whether to adopt the Staff Proposal together with the Joint Proposal. Several key issues remain and will shape the final outcome:

• How long must a COLR stay in the California LifeLine program after leaving its legacy obligations?
• What enforcement tools will hold providers accountable for their fiber deployment commitments?
• What standards must wireless service meet before it can replace wireline service?
• How will rural communities be protected under the new rules?

The Public Advocates Office will continue advocating for a framework that requires real infrastructure investment in exchange for regulatory relief, protects affordable service for low-income customers, and ensures no Californian loses communications service during the transition.

Sources

1. Public Advocates Office, “New CPUC Rulemaking on Carrier of Last Resort Obligations Will Help to Ensure No Customers Are Left Behind” . ↩
2. California Public Utilities Commission, Decision 21-02-029, Decision Adopting Wireline Provider Resiliency Strategies , February 11, 2021. ↩

Proceeding Documents

Key filings and rulings in Rulemaking R.24-06-012. For the complete record, see the CPUC proceeding docket .