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§ 4.1 — California

Radon testing in California

This page lists 201 people and firms with a current radon testing credential whose official record names California. Each row shows the credential number, the issuing body, and its own verification date. The latest record check on this page was October 13, 2026; other records may have been checked earlier. Source: CA CDPH. Verify the number before you hire.

Latest credential check October 13, 2026. Methodology Individual record dates may be earlier. CA CDPH.

Radon testingRadon mitigation

Testing listings are people credentialed to measure radon. Mitigation listings are people credentialed to install a reduction system. Some people appear on both lists when the official file says they hold both. The list is ordered by the city or county on each record. That place is where the record is filed, not a promise about where the person works.

201 listings. Type to narrow the list.

  1. Alcaraz, Jason

    current CA CDPH № 113870-RMP

    testing

    714-713-0805October 13, 2026cite ↗

  2. Alexander, Nicholas

    current CA CDPH № 110218-RMP

    testing

    927-247-7229October 13, 2026cite ↗

  3. Alvarado, Jennifer

    current CA CDPH № 17SS085-RMS

    testing

    805-844-4157October 13, 2026cite ↗

  4. Angeles, Cesar

    current CA CDPH № 23MT026

    testing

    310-310-3355October 13, 2026cite ↗

  5. Arango Garces, Santiago

    current CA CDPH № 21ST004-RMT

    testing

    954-540-0085October 13, 2026cite ↗

  6. Atallah, Michael

    current CA CDPH № 105517-RMP

    testing

    949-756-8282October 13, 2026cite ↗

  7. Ayotte, Thomas

    current CA CDPH № 114608-RMP

    testing

    916-591-8442October 13, 2026cite ↗

  8. Baldridge, Russell

    current CA CDPH № 115779-RMFT

    testing

    530-414-3815October 13, 2026cite ↗

  9. Baldwin, Michael

    current CA CDPH № 114900-RMP

    testing

    279-336-0649October 13, 2026cite ↗

  10. Batbold, Idermunkh

    current CA CDPH № 115390-RMP

    testing

    925-876-3085October 13, 2026cite ↗

  11. Bates, Chloe

    current CA CDPH № 24MS044-RMS

    testing

    971-275-3719October 13, 2026cite ↗

  12. Belland, Jessica

    current CA CDPH № 114110-RMFT

    testing

    310-218-1855October 13, 2026cite ↗

  13. Benavente, Alan

    current CA CDPH № 108692-RMP

    testing

    818-822-6152October 13, 2026cite ↗

  14. Bennett, Ellen

    current CA CDPH № 113902-RMP

    testing

    941-232-9627October 13, 2026cite ↗

  15. Bennett, Robert

    current CA CDPH № 114123-RMP

    testing

    760-696-2389October 13, 2026cite ↗

  16. Benoit, Andrew

    current CA CDPH № 115304-RMFT

    testing

    510-557-0592October 13, 2026cite ↗

  17. Bonilla, Nayeli

    current CA CDPH № 114385-RMP

    testing

    619-638-4377October 13, 2026cite ↗

  18. Braun, Rachel

    current CA CDPH № 112398-RMP

    testing

    916-899-1946October 13, 2026cite ↗

  19. Bredhoff, David

    current CA CDPH № 18G606

    testing

    914-420-2051October 13, 2026cite ↗

  20. Brickner, Kurt

    current CA CDPH № 107585-RMP

    testing

    419-957-2422October 13, 2026cite ↗

  21. Brown, James

    current CA CDPH № 116014-RMP

    testing

    916-906-2628October 13, 2026cite ↗

  22. Brumbaugh, Brett

    current CA CDPH № 111851-RMP

    testing

    419-392-2011October 13, 2026cite ↗

  23. Buenrostro, Lourdes

    current CA CDPH № 115032-RMP

    testing

    760-755-8135October 13, 2026cite ↗

  24. Burich, Matthew

    current CA CDPH № 114999-RMP

    testing

    310-415-7041October 13, 2026cite ↗

  25. Butler, Krista

    current CA CDPH № 115105-RMP

    testing

    775-770-0768October 13, 2026cite ↗

  26. Cadena, Christopher

    current CA CDPH № 115272-RMFT

    testing

    619-227-1338October 13, 2026cite ↗

  27. Calder, Vanessa

    current CA CDPH № 111818-RMP

    testing

    916-751-9568October 13, 2026cite ↗

  28. Calderon, Alfredo

    current CA CDPH № 113912-RMP

    testing

    714-473-6859October 13, 2026cite ↗

  29. Caldwell, Remington

    current CA CDPH № 105251-RMP

    testing

    510-557-0592October 13, 2026cite ↗

  30. Cantor, Michael

    current CA CDPH № 7SS001-RMS

    testing

    949-275-4950October 13, 2026cite ↗

  31. Carlton, Dana

    current CA CDPH № 110176-RMP

    testing

    775-842-5352October 13, 2026cite ↗

  32. Cheuvront, Winifred

    current CA CDPH № 109158-RMP

    testing

    502-410-5000October 13, 2026cite ↗

  33. Chmaytelli, Aref

    current CA CDPH № 16ST015

    testing

    310-576-7771October 13, 2026cite ↗

  34. Christopher, Durell

    current CA CDPH № 115311-RMP

    testing

    210-844-7355October 13, 2026cite ↗

  35. Cornejo, Joshua

    current CA CDPH № 111602-RMP

    testing

    714-396-0715October 13, 2026cite ↗

  36. Cortes, Caroline

    current CA CDPH № RMP-114802

    testing

    480-886-4783October 13, 2026cite ↗

  37. Cortez, Erick

    current CA CDPH № 114887-RMP

    testing

    714-924-6270October 13, 2026cite ↗

  38. Covarrubias, Noah

    current CA CDPH № 115069-RMP

    testing

    949-910-1440October 13, 2026cite ↗

  39. Cresta, Franklin

    current CA CDPH № 115088-RMP

    testing

    515-954-5454October 13, 2026cite ↗

  40. Cuda, Matthew

    current CA CDPH № 24MS046-RMS

    testing

    503-880-0126October 13, 2026cite ↗

  41. Cudmore, Jay

    current CA CDPH № RMP-114784

    testing

    858-752-0287October 13, 2026cite ↗

  42. Cyrulik, Gabriela

    current CA CDPH № 114327-RMP

    testing

    201-888-5423October 13, 2026cite ↗

  43. De Mayo, Sherri

    current CA CDPH № 111793-RMP

    testing

    407-414-8292October 13, 2026cite ↗

  44. Deason, Angela

    current CA CDPH № 111309-RMP

    testing

    530-570-4382October 13, 2026cite ↗

  45. Devine, Donald

    current CA CDPH № 112062-RMP

    testing

    914-263-1415October 13, 2026cite ↗

  46. Diez De Bonilla, Diego

    current CA CDPH № 115221-RMP

    testing

    619-227-1338October 13, 2026cite ↗

  47. Dirk, Ian

    current CA CDPH № 25MS065

    testing

    510-753-0011October 13, 2026cite ↗

  48. Dopke, Cameron

    current CA CDPH № 112263-RMP

    testing

    530-544-1862October 13, 2026cite ↗

  49. Dorj, Demchigsuren

    current CA CDPH № 25MS002

    testing

    952-686-3391October 13, 2026cite ↗

  50. Dorr, Phoenix

    current CA CDPH № RMP-114812

    testing

    619-916-9774October 13, 2026cite ↗

  51. Drollinger, Mark

    current CA CDPH № 11SS027-RMS

    testing

    818-246-2707October 13, 2026cite ↗

  52. Ducey, Riley

    current CA CDPH № 111239-RMP

    testing

    909-747-7110October 13, 2026cite ↗

  53. Easley, Chuck

    current CA CDPH № 106566-RMP

    testing

    612-220-1455October 13, 2026cite ↗

  54. Ellrot, Reveann

    current CA CDPH № 100519-RMP

    testing

    805-732-1272October 13, 2026cite ↗

  55. Ellrott Junior, Fred

    current CA CDPH № 113534-RMP

    testing

    805-732-2476October 13, 2026cite ↗

  56. Epperson, Jacob

    current CA CDPH № 111714-RMP

    testing

    251-360-9514October 13, 2026cite ↗

  57. Everitt, Michelle

    current CA CDPH № 114300-RMP

    testing

    301-706-6549October 13, 2026cite ↗

  58. Feathers, Nicholas

    current CA CDPH № 115958-RMP

    testing

    805-660-8800October 13, 2026cite ↗

  59. Feeney-mosier, Jonathan

    current CA CDPH № 111790-RMP

    testing

    858-401-0339October 13, 2026cite ↗

  60. Finn, Joseph

    current CA CDPH № 114277-RMP

    testing

    574-876-2294October 13, 2026cite ↗

  61. Finseth, Matthew

    current CA CDPH № 115547-RMP

    testing

    714-856-9220October 13, 2026cite ↗

  62. Ford, Brandon

    current CA CDPH № 108285-RMP

    testing

    530-544-1862October 13, 2026cite ↗

  63. Frayman, Daniel

    current CA CDPH № 116116-RMP

    testing

    818-749-8576October 13, 2026cite ↗

  64. Furman, Melanie

    current CA CDPH № 21ST032

    testing

    561-893-7437October 13, 2026cite ↗

  65. Gabriel, Macias

    current CA CDPH № 116102-RMP

    testing

    909-358-0478October 13, 2026cite ↗

  66. Garcia-osorio, Fernando

    current CA CDPH № 115030-RMP

    testing

    805-404-0769October 13, 2026cite ↗

  67. Garcia, Miguel

    current CA CDPH № 112005-RMP

    testing

    714-240-8651October 13, 2026cite ↗

  68. Gengenbacher, David

    current CA CDPH № 111074-RMP

    testing

    562-235-6654October 13, 2026cite ↗

  69. Gibson, Martin

    current CA CDPH № 112919-RMP

    testing

    512-955-1161October 13, 2026cite ↗

  70. Gilley, Kimberly

    current CA CDPH № 25MS008

    testing

    614-516-3398October 13, 2026cite ↗

  71. Grandstaff, Stephanie

    current CA CDPH № 113872-RMP

    testing

    813-244-8283October 13, 2026cite ↗

  72. Graves, Jordan

    current CA CDPH № 115393-RMP

    testing

    562-746-8887October 13, 2026cite ↗

  73. Greenfield, Zachary

    current CA CDPH № 114895-RMP

    testing

    818-424-9224October 13, 2026cite ↗

  74. Gregory, Jason

    current CA CDPH № 107969-RMP

    testing

    805-244-6687October 13, 2026cite ↗

  75. Gress, Jeremy

    current CA CDPH № 107060-RMP

    testing

    949-677-7122October 13, 2026cite ↗

  76. Grissette, Alain

    current CA CDPH № 105206-RMP

    testing

    925-808-6700October 13, 2026cite ↗

  77. Grondin, Nathaniel

    current CA CDPH № 113883-RMT

    testing

    774-275-4600October 13, 2026cite ↗

  78. Groves, Brandy

    current CA CDPH № 113475-RMP

    testing

    951-816-0518October 13, 2026cite ↗

  79. Grunat, David

    current CA CDPH № 114095-RMP

    testing

    510-756-0741October 13, 2026cite ↗

  80. Hanson, Sean

    current CA CDPH № 25MS026-RMS

    testing

    657-365-9041October 13, 2026cite ↗

  81. Hardesty, Esther

    current CA CDPH № 110925-RMP

    testing

    720-935-0652October 13, 2026cite ↗

  82. Harreschou, Murray

    current CA CDPH № 12SS002-RMS

    testing

    310-396-6532October 13, 2026cite ↗

  83. Harreschou, Samuel

    current CA CDPH № 108234-RMP

    testing

    310-903-86 56October 13, 2026cite ↗

  84. Head, Robert

    current CA CDPH № 115440-RMP

    testing

    805-419-1231October 13, 2026cite ↗

  85. Henderson, John

    current CA CDPH № 108870-RMP

    testing

    805-280-6616October 13, 2026cite ↗

  86. Henderson, Lisa

    current CA CDPH № 113942-RMP

    testing

    714-349-5760October 13, 2026cite ↗

  87. Hirsch, Elizabeth

    current CA CDPH № 115177-RMP

    testing

    509-948-8360October 13, 2026cite ↗

  88. Hodges, Robert

    current CA CDPH № 112099-RMP

    testing

    309-231-8223October 13, 2026cite ↗

  89. Hohne, Matt

    current CA CDPH № 113405-RMP

    testing

    949-528-5320October 13, 2026cite ↗

  90. Huchingson, Eddie

    current CA CDPH № 107620-RMP

    testing

    805-908-9274October 13, 2026cite ↗

  91. Huchingson, Tracy

    current CA CDPH № 110443-RMP

    testing

    805-908-9274October 13, 2026cite ↗

  92. Huerta, Danny

    current CA CDPH № 112948-RMP

    testing

    213-507-0917October 13, 2026cite ↗

  93. Humphrey, Donald

    current CA CDPH № 107688-RMP

    testing

    303-444-5253October 13, 2026cite ↗

  94. Ironi, Dennis

    current CA CDPH № 102942-RMP

    testing

    310-854-5453October 13, 2026cite ↗

  95. Jones, Dallas

    current CA CDPH № 114061-RMP

    testing

    678-983-9312October 13, 2026cite ↗

  96. Jordan, Christine

    current CA CDPH № 100318-RMP

    testing

    562-495-5777October 13, 2026cite ↗

  97. Kading Inland Empire, William

    current CA CDPH № 22SS005-RMS

    testing

    951-300-8396October 13, 2026cite ↗

  98. Kalman, Tucker

    current CA CDPH № 108599-RMP

    testing

    415-723-0962October 13, 2026cite ↗

  99. Kellogg, Bonnie

    current CA CDPH № 102253-RMP

    testing

    510-786-9751October 13, 2026cite ↗

  100. Kim, Brian

    current CA CDPH № 23MT038

    testing

    415-310-5067October 13, 2026cite ↗

  101. Kim, Juhun

    current CA CDPH № 114237-RMP

    testing

    909-827-0035October 13, 2026cite ↗

  102. Koka, Bradon

    current CA CDPH № 112704-RMP

    testing

    925-389-3787October 13, 2026cite ↗

  103. Krmpotich, Kyle

    current CA CDPH № 115050-RMP

    testing

    949-502-5353October 13, 2026cite ↗

  104. Laborde, Lynn

    current CA CDPH № 113778-RMP

    testing

    909-645-3826October 13, 2026cite ↗

  105. Lahti, Martha

    current CA CDPH № 114810-RMP

    testing

    774-473-0921October 13, 2026cite ↗

  106. Laurent, Tanya

    current CA CDPH № 109217-RMP

    testing

    562-303-5219October 13, 2026cite ↗

  107. Lorgoni, Alina

    current CA CDPH № 116034-RMP

    testing

    714-434-6360October 13, 2026cite ↗

  108. Luna, James

    current CA CDPH № 116044-RMP

    testing

    909-764-4483October 13, 2026cite ↗

  109. Mandel, Ryan

    current CA CDPH № 114730-RMP

    testing

    510-300-7404October 13, 2026cite ↗

  110. Manshour, Tony

    current CA CDPH № 110242-RMP

    testing

    661-341-1707October 13, 2026cite ↗

  111. Mansour, Ahmad

    current CA CDPH № 114665-RMT

    testing

    510-304-2249October 13, 2026cite ↗

  112. Marcus, Brooklyn

    current CA CDPH № 113748-RMP

    testing

    310-294-0700October 13, 2026cite ↗

  113. Mares, Jorge

    current CA CDPH № 115549-RMP

    testing

    408-512-2912October 13, 2026cite ↗

  114. Marion, Trevor

    current CA CDPH № 107194-RMP

    testing

    925-787-8411October 13, 2026cite ↗

  115. Marquez, Philip

    current CA CDPH № 112019-RMP

    testing

    559-939-7935October 13, 2026cite ↗

  116. Marshall, Cameros

    current CA CDPH № 115908-RMP

    testing

    409-295-0210October 13, 2026cite ↗

  117. Martini, Cory

    current CA CDPH № 107918-RMP

    testing

    916-838-7365October 13, 2026cite ↗

  118. Mason, Emily

    current CA CDPH № 26MS019

    testing

    406-396-7235October 13, 2026cite ↗

  119. Massey, Jonathan

    current CA CDPH № 13SS057-RMS

    testing

    310-978-8281October 13, 2026cite ↗

  120. Matecki, Christian

    current CA CDPH № 107105-RMP

    testing

    602-663-2270October 13, 2026cite ↗

  121. McKenzie, Ross

    current CA CDPH № 115074-RMP

    testing

    925-436-8000October 13, 2026cite ↗

  122. McMahon, Riley

    current CA CDPH № 24MS002-RMS

    testing

    480-435-1670October 13, 2026cite ↗

  123. Melchior, Ronald

    current CA CDPH № RMP-112634

    testing

    443-790-4613October 13, 2026cite ↗

  124. Merrill, Dawn

    current CA CDPH № 115329-RMP

    testing

    562-860-2869October 13, 2026cite ↗

  125. Midmore, Tony

    current CA CDPH № 114256-RMP

    testing

    775-323-1117October 13, 2026cite ↗

  126. Minto, Kevin

    current CA CDPH № 110412-RMP

    testing

    530-273-1300October 13, 2026cite ↗

  127. Miranda, Alexandria

    current CA CDPH № 113855-RMP

    testing

    916-918-5397October 13, 2026cite ↗

  128. Moschella, Joseph

    current CA CDPH № 23MT027

    testing

    310-978-8281October 13, 2026cite ↗

  129. Munoz, Jennifer

    current CA CDPH № 2MS049

    testing

    818-302-9724October 13, 2026cite ↗

  130. Nguyen, Jerry

    current CA CDPH № 115975-RMP

    testing

    714-251-8513October 13, 2026cite ↗

  131. Nishio, Andrew

    current CA CDPH № 114863-RMP

    testing

    714-434-6360October 13, 2026cite ↗

  132. Noel, Jeffrey

    current CA CDPH № 102014-RMP

    testing

    559-348-2200October 13, 2026cite ↗

  133. Noland, Carol

    current CA CDPH № 9SS0048-RMS

    testing

    805-214-6378October 13, 2026cite ↗

  134. O'neil, Joan

    current CA CDPH № 115705-RMP

    testing

    510-293-3009October 13, 2026cite ↗

  135. Olsen, Christopher

    current CA CDPH № 114306-RMP

    testing

    831-262-8859October 13, 2026cite ↗

  136. Osborne, Joshua

    current CA CDPH № 114915-RMP

    testing

    415-967-6043October 13, 2026cite ↗

  137. Overton, William

    current CA CDPH № 324MS092-RMS

    testing

    760-613-4696October 13, 2026cite ↗

  138. Pallin, Bjoern

    current CA CDPH № 115834-RMP

    testing

    279-251-5300October 13, 2026cite ↗

  139. Pangilinan, Natalie

    current CA CDPH № 114822-RMP

    testing

    279-900-5851October 13, 2026cite ↗

  140. Peacock, Amy

    current CA CDPH № 109996-RMP

    testing

    913-484-1532October 13, 2026cite ↗

  141. Pearce, Taylor

    current CA CDPH № 2SMS042

    testing

    775-827-2717October 13, 2026cite ↗

  142. Phan, Breanna

    current CA CDPH № 113717-RMP

    testing

    209-314-7353October 13, 2026cite ↗

  143. Pinkerton, Michael

    current CA CDPH № 106593-RMP

    testing

    310-854-6300October 13, 2026cite ↗

  144. Prater, Daniel

    current CA CDPH № 108446-RMP

    testing

    408-655-2696October 13, 2026cite ↗

  145. Prunty, Derek

    current CA CDPH № 112914-RMP

    testing

    304-657-5261October 13, 2026cite ↗

  146. Quach, Derrick

    current CA CDPH № 104582-RMP

    testing

    510-786-9751October 13, 2026cite ↗

  147. Ramos, Jorge

    current CA CDPH № 114953-RMP

    testing

    714-499-7659October 13, 2026cite ↗

  148. Rhea, David

    current CA CDPH № 114735-RMP

    testing

    858-220-9995October 13, 2026cite ↗

  149. Riley, Edward

    current CA CDPH № 106364-RMP

    testing

    530-583-6653October 13, 2026cite ↗

  150. Roberts, Curtis

    current CA CDPH № 115794-RMP

    testing

    916-690-4884October 13, 2026cite ↗

  151. Robins, Reed

    current CA CDPH № 113945-RMP

    testing

    719-233-3466October 13, 2026cite ↗

  152. Robinson, Thomas

    current CA CDPH № 115403-RMP

    testing

    805-815-5025October 13, 2026cite ↗

  153. Rodriguez, Heri

    current CA CDPH № 107994-RMP

    testing

    323-551-8449October 13, 2026cite ↗

  154. Rodriquez, Micaela

    current CA CDPH № 24MT026-RMT

    testing

    510-694-6002October 13, 2026cite ↗

  155. Rosengarten, Rob

    current CA CDPH № 111859-RMP

    testing

    630-246-0745October 13, 2026cite ↗

  156. Ross, Aidan

    current CA CDPH № 115061-RMP

    testing

    858-868-1929October 13, 2026cite ↗

  157. Ruiz, Luis

    current CA CDPH № 116662-RMP

    testing

    619-638-4377October 13, 2026cite ↗

  158. Sabal, Malcolm

    current CA CDPH № 114219-RMS

    testing

    310-415-8749October 13, 2026cite ↗

  159. Sahakian, Eliza

    current CA CDPH № 114248-RMP

    testing

    626-354-9554October 13, 2026cite ↗

  160. Saturno, Stephen

    current CA CDPH № 109015-RMP

    testing

    530-414-3815October 13, 2026cite ↗

  161. Scherr, Katrina

    current CA CDPH № 113718-RMP

    testing

    916-458-1098October 13, 2026cite ↗

  162. Schmidt, Kristen

    current CA CDPH № 108034-RMP

    testing

    630-479-2507October 13, 2026cite ↗

  163. Schoenberger, Sophie

    current CA CDPH № 25MS024-RMS

    testing

    920-536-2002October 13, 2026cite ↗

  164. Schulte-bisping, Benjamin

    current CA CDPH № 115025-RMP

    testing

    510-773-0708October 13, 2026cite ↗

  165. Schweiger, Matthew

    current CA CDPH № 115838-RMP

    testing

    951-283-2823October 13, 2026cite ↗

  166. Sciumbato, Troy

    current CA CDPH № 109694-RMP

    testing

    559-416-6134October 13, 2026cite ↗

  167. Seward, Nate

    current CA CDPH № 108180-RMP

    testing

    805-432-4888October 13, 2026cite ↗

  168. Shockley, Karen

    current CA CDPH № 9SS0029-RMS

    testing

    619-276-5901October 13, 2026cite ↗

  169. Shockley, Milton

    current CA CDPH № 9SS0030-RMS

    testing

    619-276-5901October 13, 2026cite ↗

  170. Snyder, Steven

    current CA CDPH № 21ST005-RMT

    testing

    732-618-0844October 13, 2026cite ↗

  171. Sottek, John

    current CA CDPH № 115292-RMP

    testing

    714-523-2033October 13, 2026cite ↗

  172. Sunil, Shipla

    current CA CDPH № 25MS016

    testing

    949-307-3522October 13, 2026cite ↗

  173. Swingle, Anahita

    current CA CDPH № 25MS018-RMS

    testing

    714-721-4111October 13, 2026cite ↗

  174. Talley, John

    current CA CDPH № 115856-RMP

    testing

    812-483-0034October 13, 2026cite ↗

  175. Thornberry, Phil

    current CA CDPH № 100753-RMP

    testing

    317-853-2172October 13, 2026cite ↗

  176. Tillema, David

    current CA CDPH № 106759-RMP

    testing

    949-289-3568October 13, 2026cite ↗

  177. Torres, Carlo

    current CA CDPH № 112829-RMP

    testing

    310-357-1067October 13, 2026cite ↗

  178. Tumbale, Sebastian

    current CA CDPH № 115667-RMFT

    testing

    530-544-1862October 13, 2026cite ↗

  179. Valdez, John

    current CA CDPH № 115251-RMP

    testing

    619-578-1462October 13, 2026cite ↗

  180. Vejar, Ramior

    current CA CDPH № 113725-RMP

    testing

    909-333-8592October 13, 2026cite ↗

  181. Ventura, Daniel

    current CA CDPH № 115340-RMP

    testing

    916-890-4674October 13, 2026cite ↗

  182. Villacorta, Estella

    current CA CDPH № 115800-RMP

    testing

    714-293-7207October 13, 2026cite ↗

  183. Villanueva, Daniel

    current CA CDPH № 115239-RMP

    testing

    619-638-3679October 13, 2026cite ↗

  184. Villanueva, Jose

    current CA CDPH № 114034-RMP

    testing

    619-592-3967October 13, 2026cite ↗

  185. Waldman, Carsyn

    current CA CDPH № 26MT004

    testing

    728-219-5175October 13, 2026cite ↗

  186. Warden, Alice

    current CA CDPH № 114864-RMP

    testing

    714-434-6360October 13, 2026cite ↗

  187. Warner, Nathan

    current CA CDPH № 115502-RMP

    testing

    559-355-5828October 13, 2026cite ↗

  188. Watson, Tracy

    current CA CDPH № 109320-RMP

    testing

    713-854-8670October 13, 2026cite ↗

  189. Weber, Karen

    current CA CDPH № 23MS059-RMS

    testing

    630-325-4443October 13, 2026cite ↗

  190. Westcott, Jeremy

    current CA CDPH № 112497-RMP

    testing

    734-649-9680October 13, 2026cite ↗

  191. Wheeler, Randall

    current CA CDPH № 23MS026-RMS

    testing

    734-649-9680October 13, 2026cite ↗

  192. Williams, Joe

    current CA CDPH № 110831-RMP

    testing

    714-434-6360October 13, 2026cite ↗

  193. Williams, John

    current CA CDPH № 115235-RMFT

    testing

    760-594-1625October 13, 2026cite ↗

  194. Williamson, Kathleen

    current CA CDPH № 103081-RMP

    testing

    860-298-6392October 13, 2026cite ↗

  195. Wood, Judith

    current CA CDPH № 106128-RMP

    testing

    805-563-0100October 13, 2026cite ↗

  196. Xiao, Jane

    current CA CDPH № 23MS076-RMS

    testing

    628-233-7258October 13, 2026cite ↗

  197. Yamauchi, Scott

    current CA CDPH № 114036-RMP

    testing

    714-831-7591October 13, 2026cite ↗

  198. Zeidan, Ted

    current CA CDPH № 115002-RMP

    testing

    818-639-2396October 13, 2026cite ↗

  199. Zharkov, Lurii

    current CA CDPH № 115915-RMS

    testing

    213-460-4929October 13, 2026cite ↗

  200. Zhdanyuk, Oleksandr

    current CA CDPH № 110094-RMP

    testing

    916-206-0829October 13, 2026cite ↗

  201. Zivolich, Steve

    current CA CDPH № 105129-RMP

    testing

    707-239-2601October 13, 2026cite ↗

Appendix A

Questions before you hire

How do I verify a radon credential listed for California?

Open the source link on this page and match the name and credential number to CA CDPH. Status can change after a record’s verification date. The latest record check on this page was October 13, 2026; check each record’s date. If the official page disagrees with this directory, trust the official page. We do not invent credential numbers.

Does EPA certify radon contractors?

The U.S. EPA does not certify radon contractors. EPA publishes guidance on finding a qualified radon service provider and points to state programs and national certifications. This directory is not affiliated with EPA. We do not display EPA-certified badges.

What does last verified mean on this page?

Last verified on an individual record is the date we checked its official source. The latest credential check on this page was October 13, 2026; other records may have earlier dates. We refresh the roster monthly. Current means the person appeared as currently credentialed on the source at that record’s verification date. Credentials can expire between refreshes, so follow the source link.

Appendix A.2

Before you hire

  1. Ask who holds the credential printed on this page, and ask them to show the same number. Some firms employ several credentialed people. The listing is the person or firm on the official file, not whoever answers the phone.
  2. Ask what test method or mitigation system they will use for this building. A credential is not a work plan. Testing and mitigation are separate services here, and a person appears on both lists only when the official file says they hold both.
  3. Ask how they will document test results or the finished mitigation system. Keep that document with the credential number you verified. This directory does not score jobs, publish reviews, or collect quotes.

The full checklist: Certified radon tester: what they do and how to hire one

California CDPH lists radon testers and mitigators certified to operate in California. The people below appear with a current expiration date on that file. CDPH does not publish city or county, so this site does not invent city pages. Read the methodology. Credential status can change.