Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

William Merrit Fox, LCSW

Clinical Social Worker in Walnut Creek, CA · enumerated 2007.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1083893143

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Registry record

Entity type Individual (Type 1)

Name William Merrit Fox

Credential LCSW

Sex Male

Practice address Walnut Creek, CA, 94597

Phone (925) 282-1778

Fax (415) 296-5299

Enumeration date Oct 25, 2007

Last updated in NPPES May 6, 2024

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License LCSW13038 (CA) Primary

LCSW · Licensed Clinical Social Worker: A social worker licensed for clinical practice including mental-health therapy. About the LCSW credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is William Fox?

William Fox is registered in NPPES with the primary taxonomy of Clinical Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-05-06.