William Mains, M.D.
NPI 1477751741 · Addiction Psychiatry Physician · Oakland, CA
Enrolled with Medicare as Practitioner - Psychiatry · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Mains, M.D. is a Addiction Psychiatry Physician provider in Oakland, CA (NPI 1477751741).
Provider details
- NPI number
- 1477751741
- Entity type
- Individual
- Primary specialty
- Addiction Psychiatry PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A65356 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
18 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
32 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Residence Visit for Established Patient With Low Level of Medical Decision Making, Per Day, If Using Time, at Least 30 Minutes99348 | 32 | $87 |
Typical Medicare-allowed amounts for these services range $87–$87 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 21 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Olanzapine | 126 | 14 |
| Aripiprazole | 63 | — |
| Gabapentin | 46 | — |
| Risperidone | 40 | — |
| Mirtazapine | 37 | — |
| Fluoxetine Hcl | 32 | — |
| Divalproex Sodiumbrand: Divalproex Sodium Er | 31 | — |
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-07-06
- Last updated
- 2010-01-07
Frequently asked questions
- What is William Mains's NPI number?
- William Mains's National Provider Identifier (NPI) is 1477751741, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Mains's specialty?
- William Mains is listed in the NPPES registry with a primary specialty of Addiction Psychiatry Physician (Allopathic & Osteopathic Physicians).
- Where is William Mains located?
- William Mains's practice location on file with NPPES is 7200 Bancroft Ave, Oakland, CA 94605-2403.
- What is William Mains's phone number?
- The practice phone number listed in the NPPES registry for William Mains is (510) 553-8500.
- Does William Mains accept Medicare?
- William Mains is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Mains's NPI active?
- Yes — William Mains's NPI (1477751741) is active in the NPPES registry as of the last update on 2010-01-07.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.