Siobhan Mark, MS CCC-SLP
NPI 1487141974 · Speech-Language Pathologist · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Qualified Speech Language Pathologist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Siobhan Mark, MS CCC-SLP is a Speech-Language Pathologist provider in Walnut Creek, CA (NPI 1487141974).
Provider details
- NPI number
- 1487141974
- Entity type
- Individual
- Primary specialty
- Speech-Language PathologistSpeech, Language and Hearing Service Providers
- Credential
- MS CCC-SLP
- Sex
- Female
- Sole proprietor
- Yes
- License
- 12149 (CA)
Specialties & taxonomies
Speech, Language and Hearing Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
8 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
2 documented practice locations
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
Additional practice locations (1)
- 1425 S Main StWalnut Creek, CA 94596-5318Phone: (925) 295-4000
Registry dates
- Enumerated
- 2018-04-19
- Last updated
- 2022-02-11
Frequently asked questions
- What is Siobhan Mark's NPI number?
- Siobhan Mark's National Provider Identifier (NPI) is 1487141974, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Siobhan Mark's specialty?
- Siobhan Mark is listed in the NPPES registry with a primary specialty of Speech-Language Pathologist (Speech, Language and Hearing Service Providers).
- Where is Siobhan Mark located?
- Siobhan Mark's practice location on file with NPPES is 320 Lennon Ln, Walnut Creek, CA 94598-2419.
- What is Siobhan Mark's phone number?
- The practice phone number listed in the NPPES registry for Siobhan Mark is (925) 906-2000.
- Does Siobhan Mark accept Medicare?
- Siobhan Mark is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Siobhan Mark's NPI active?
- Yes — Siobhan Mark's NPI (1487141974) is active in the NPPES registry as of the last update on 2022-02-11.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.