William Mazzarella, COUNSELOR
NPI 1770787111 · Addiction (Substance Use Disorder) Registered Nurse · San Diego, CA
William Mazzarella, COUNSELOR is a Addiction (Substance Use Disorder) Registered Nurse provider in San Diego, CA (NPI 1770787111).
Provider details
- NPI number
- 1770787111
- Entity type
- Individual
- Primary specialty
- Addiction (Substance Use Disorder) Registered NurseNursing Service Providers
- Credential
- COUNSELOR
- Sex
- Male
- Sole proprietor
- No
- License
- 530630 (CA)
Specialties & taxonomies
Nursing Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-06-11
- Last updated
- 2026-05-17
- Certified
- 2026-05-17
Frequently asked questions
- What is William Mazzarella's NPI number?
- William Mazzarella's National Provider Identifier (NPI) is 1770787111, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Mazzarella's specialty?
- William Mazzarella is listed in the NPPES registry with a primary specialty of Addiction (Substance Use Disorder) Registered Nurse (Nursing Service Providers).
- Where is William Mazzarella located?
- William Mazzarella's practice location on file with NPPES is 2456 E St, San Diego, CA 92102-2024.
- What is William Mazzarella's phone number?
- The practice phone number listed in the NPPES registry for William Mazzarella is (619) 503-7680.
- Is William Mazzarella's NPI active?
- Yes — William Mazzarella's NPI (1770787111) is active in the NPPES registry as of the last update on 2026-05-17.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.