William J. Delo, DO
Family Medicine Physician · Fontana, CA
William J. Delo, DO is a family medicine physician with a practice address in Fontana, California, and NPI 1033286919, issued on Nov 29, 2006. Check the license (California 20A6548, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William J. Delo
- Credential
- DO
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- 20A6548 CA
Self-reported in NPPES; status is on the state search - Practice location
- 9961 Sierra Ave, Fontana, CA 92335
- Phone
- (909) 427-3910
- Enumerated
- Nov 29, 2006
- Record last updated
- Dec 2, 2021 (not updated in 5 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Also registered at 9961 Sierra Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William J. Delo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A6548Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
95% fewer Medicare Part D claims than the average family medicine physician in 2024
181 Medicare Part D claims for 106 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D.
Most prescribed
- Albuterol Sulfate Hfa15 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
William J. Delo among 17,133 family medicine physician records in California
William J. Delo, DO is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 6% of them.
- NPI issued2006 · 6% of these records are older, 59% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 62% of these records are
- Record last updated2021 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
198 family medicine physician records list a practice address in Fontana
They are 198 of the 3,012 NPPES records with a practice address in Fontana, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Fontana → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Frances Burke, MDFontana, CA 923351972674901
- Nathan Carlson, M.D.Fontana, CA 923351144212929
- Christine Carlson, MDFontana, CA 923351386612299
- Thawat Eosakul, M.D.Fontana, CA 923351811904519
- Diane Hom, MDFontana, CA 923351821169707
- Anissa Lacount, MDFontana, CA 923351609854397
- Rubin Lin, D.O.Fontana, CA 923351679678916
- Lannie Moy, PA-CFontana, CA 923351922037738
Common questions
What is William J. Delo, DO's NPI number?
William J. Delo, DO's National Provider Identifier (NPI) is 1033286919, issued on Nov 29, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William J. Delo, DO located?
The NPPES record lists a practice address at 9961 Sierra Ave, Fontana, CA, 92335. Phone: (909) 427-3910. Providers update this record themselves, so call before visiting.
How can I verify William J. Delo, DO's license?
NPPES lists California license number 20A6548, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William J. Delo, DO prescribe under Medicare Part D?
In 2024, William J. Delo, DO had 181 Medicare Part D claims for 106 beneficiaries; the average among family medicine physician prescribers was 3,544. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.