Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Mr. Wiliam David Hirschaut, MSW
Social Worker in Lexington, MA · enumerated 2008.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1568615599
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Registry record
Entity type Individual (Type 1)
Name Mr. Wiliam David Hirschaut
Credential MSW
Sex Male
Practice address 1040 Waltham St, Lexington, MA, 02421
Phone (781) 862-3600
Fax (781) 860-7636
Enumeration date Nov 4, 2008
Last updated in NPPES Nov 4, 2008
Taxonomy & licenses
Other identifiers
| Identifier | Type | State | Issuer |
|---|---|---|---|
| M18633 | Other | MA | BCBS |
| 1303287 | Other | MA | MBHP |
| 1004745 | Other | MA | NHP |
| 99618201 | Other | MA | NETWORK HEALTH |
| 0000023532 | Other | MA | BMC |
| 042611055 | Other | MA | TAX ID |
| 1303287 | Medicaid | MA | - |
| 703136 | Other | MA | TUFTS |
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
What specialty is Wiliam Hirschaut?
Wiliam Hirschaut is registered in NPPES with the primary taxonomy of Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Other providers at this practice address
Browse all → John Costanzo Mental Health Counselor · Lexington, MA NPI 1447311196 Daniel Julian Mental Health Counselor · Lexington, MA NPI 1922207760 Lynn Nanos Clinical Social Worker · Lexington, MA NPI 1902098353 Denise Moyo Mental Health Counselor · Lexington, MA NPI 1003056177 Lucy Hall Clinical Social Worker · Lexington, MA NPI 1477797918 Heather Harris Mental Health Counselor · Lexington, MA NPI 1235469024 Michael O'Neill Mental Health Counselor · Lexington, MA NPI 1912237520 Fong Chan Mental Health Counselor · Lexington, MA NPI 1336479914
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2008-11-04.