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Internal Medicine

James Waterhouse, MD

Sees patients in San Leandro, CA · California

Summary

Dr. James Waterhouse, MD is an internal medicine doctor at 2500 Merced St, San Leandro, CA 94577. Phone: (510) 454-1000. Accepts Medicare assignment. In 2024, James Waterhouse had 13 Original Medicare patients and 18 services. NPI 1881772630. Source: CMS National Downloadable File, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Internal medicine doctor (Medicare lists Internal Medicine)
  • Address: 2500 Merced St, San Leandro, CA 94577 · Directions
  • Phone: (510) 454‑1000
  • Medicare: Accepts Medicare assignment
  • Group practice: Permanente Medical Group Inc
  • Medical school: University Of Tennessee, Hsc, College Of Medicine · graduated 1984 (42 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about James Waterhouse, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does James Waterhouse accept Medicare assignment?
Yes. Medicare's clinician data says James Waterhouse accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does James Waterhouse see?
In 2024, CMS data shows 13 Original Medicare patients and 18 services for James Waterhouse. This counts Original Medicare only and measures volume, not quality.
What is James Waterhouse's NPI number?
1881772630. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for James Waterhouse, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients13
Services billed to Medicare18
Different services or procedures8
Participating Medicare providerYes
Average age of these patients62

Practice locations

Addresses where James Waterhouse is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists James Waterhouse as a member of this group (CMS data updated October 2, 2026).

  • Permanente Medical Group Inc10,996 clinicians in the group

Specialties

Find other Internal Medicine doctors in California →

Other internal medicine doctors in San Leandro

Clinicians with the same Medicare primary specialty in San Leandro, CA — not a recommendation.

All internal medicine doctors in San Leandro →

Other clinicians in Permanente Medical Group Inc

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolUniversity Of Tennessee, Hsc, College Of Medicine
Graduation year1984 (42 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1881772630
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians