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WILLIAM LARKIN LCSW
NPI 1629559299
Social Worker - Clinical in Chino Hills, CA

Active since August 22, 2018PECOS Enrolled
4045 BAYBERRY DR, CHINO HILLS, CA 91709(909) 680-8161 Get Directions Write a Review

NPPES record last updated: October 4, 2023. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Oct 4, 2023, Aug 22, 2018 (2 updates tracked since 2018).

About William Larkin Lcsw NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

WILLIAM LARKIN LCSW (NPI 1629559299) is an individual clinical provider in Chino Hills, California, licensed in California (118024) and active in the NPI registry since August 2018. He is enrolled in Medicare PECOS and is a graduate of Other (2019).

NPPES Registry Identity

NPI1629559299
Entity TypeIndividualMale
Primary Taxonomy1041C0700X
Provider Legal NameWILLIAM LARKINCredential: LCSW
Location Address4045 BAYBERRY DRChino Hills, CA 91709-3311
Mailing Address4045 Bayberry DrChino Hills, CA 91709-3311 · (909) 680-8161
Phone(909) 680-8161
Sole ProprietorYes
Medical School CMSOtherGraduated 2019
Enumeration DateAugust 22, 2018
Last NPPES UpdateOctober 4, 20232 updates tracked since enumeration
NPPES CertifiedOctober 4, 2023
✔ NPI 1629559299 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtySocial Worker · ClinicalBehavioral Health & Social Service Providers
Taxonomy Code1041C0700X
License✔ Licensed in CA · 118024
Definition
A social worker who holds a master's or doctoral degree in social work from an accredited school of social work in addition to at least two years of post-master's supervised experience in a clinical setting. The social worker must be licensed, certified, or registered at the clinical level in the jurisdiction of practice. A clinical social worker provides direct services, including interventions focused on interpersonal interactions, intrapsychic dynamics, and life management issues. Clinical social work services are based on bio-psychosocial perspectives. Services consist of assessment, diagnosis, treatment (including psychotherapy and counseling), client-centered advocacy, consultation, evaluation, and prevention of mental illness, emotional, or behavioral disturbances.
Also ListedCounselor · Addiction (Substance Use Disorder)Taxonomy 101YA0400X
4045 BAYBERRY DR, Chino Hills, CA 91709
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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

William Larkin Lcsw is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

PECOS PAC ID6103385836
PECOS Enrollment IDI20260824002660
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment– Home Health Agency– Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignment

Medicare enrollment records show William Larkin reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Grow Healthcare Group PC
330 mi
Mental Health
99 S ALMADEN BLVD STE 600
San Jose, CA 95113
  • Reassigned Medicare billing, California enrollment
  • 3,139 clinicians in this Medicare group
NPI 1154994846 (408) 402-4385

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 91709 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$0.00 typical visit price
range $59.60 – $179.42
Typical copayment $0.00 (range $14.90 – $44.85)
Most-billed visit code NA
Established Patient
$74.08 typical visit price
range $19.37 – $146.42
Typical copayment $18.52 (range $4.84 – $36.60)
Most-billed visit code 99213
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is William Larkin's NPI number?

The NPI number for William Larkin is 1629559299. It was assigned to this individual provider in the NPPES registry on August 22, 2018.

Where is William Larkin located?

William Larkin practices at 4045 Bayberry Dr, Chino Hills, CA 91709. The listed phone number is (909) 680-8161.

What is William Larkin's specialty?

The primary specialty registered for this NPI is Social Worker, specializing in Clinical, with taxonomy code 1041C0700X.

Is William Larkin enrolled in Medicare?

Yes. William Larkin is registered in the Medicare PECOS enrollment system.

Which organization bills Medicare for William Larkin's services?

According to the CMS Revalidation Reassignment List (October 2026 release), William Larkin reassigns Medicare benefits to Grow Healthcare Group PC (San Jose, CA). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for William Larkin's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for William Larkin was last updated on October 4, 2023. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 3 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.