Walter Nielson
Walter Nielson is a Marriage & Family Therapist in Fairfield, CA, registered under NPI 1003183088. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
Here is what surrounds this office in Fairfield, based on OpenStreetMap data collected Sep 2, 2026. Parking is available about 478 ft away. The nearest transit stop is 776 ft away, served by Fairfield Civic Center. If you arrive early, there is a coffee shop 0.24 mi away.
Getting here and what is nearby
Parking 139 ft ~1 min
Transit Pennsyvlania Ave and Kentucky St 214 ft ~1 min
Parking 301 ft ~2 min
Parking 478 ft ~2 min
Transit Fairfield Civic Center 608 ft ~3 min
Transit Fairfield Civic Center 776 ft ~3 min
Gas station Chevron 784 ft ~3 min
Convenience Circle K 0.23 mi ~5 min
Gas station 76 0.23 mi ~5 min
Hotel Econo Lodge 0.23 mi ~5 min
Coffee Dutch Bros. Coffee 0.24 mi ~5 min
1420 West Texas Street, Fairfield 94533
Mo 05:30-22:00; Tu 05:30-17:00; We-Th 05:30-22:00; Fr-Sa 05:30-23:00; Su 05:30-22:00
Restaurant Joe’s Buffet 0.30 mi ~6 min
834 Texas Street, Fairfield 94533
Restaurant Subway 0.39 mi ~8 min
1513 West Texas Street, Fairfield 94533
Mo-Sa 08:00-21:30; Su 09:00-21:00
Restaurant Three Restaurant 0.40 mi ~8 min
Distances are straight‑line estimates — walking routes may be longer. Hours and phone numbers can change; call ahead to confirm.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| IMF78099 | CA | Mental Health Counselor |
| 116511 | CA | Mental Health Counselor |
| 116511 | CA | Marriage & Family Therapist |
| 132820 | CA | Marriage & Family Therapist primary |
This provider holds licence IMF78099 issued in CA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Marriage & Family Therapist covers
A marriage and family therapist is a person with a master's degree in marriage and family therapy, or a master's or doctoral degree in a related mental health field with substantially equivalent coursework in marriage and family therapy, who receives supervised clinical experience, or a person who meets the state requirements to practice as a marriage and family therapist. A marriage and family therapist treats mental and emotional disorders within the context of marriage and family systems. A marriage and family therapist provides mental health and counseling services to individuals, couples, families, and groups. NUCC Health Care Provider Taxonomy, code 106H00000X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 101YM0800X | Mental Health Counselor Mental Health | IMF78099 | CA | |
| 101YM0800X | Mental Health Counselor Mental Health | 116511 | CA | |
| 106H00000X | Marriage & Family Therapist | 116511 | CA | |
| 106H00000X | Marriage & Family Therapist | 132820 | CA | primary |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1003183088 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Nov 19, 2011 |
| Last updated | May 19, 2023 |
| Status | Active |
| Sole proprietor | Yes |
| Gender | Male |
| Practice address |
1234 EMPIRE ST Fairfield, CA 94533 (707) 439-7830 |
| Mailing address |
4425 TROPAZ LN Tracy, CA 95377 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 0 | 3 | 1 | 8 | 3 | 0 | 8 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 2 | 8 | 6 | 0 | 7 |
Sum = 52 · next multiple of 10 = 60 · check digit = 8 · actual last digit = 8
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.