| 1 | Raab Well Drilling, Inc. | 971 | 2,408 | 2,909 |
| 2 | Ameridrill, Inc. | 391 | 743 | 5,442 |
| 3 | F E Buehler & Son, Inc. | 324 | 2,470 | 2,826 |
| 4 | Mayer's Well Drilling | 286 | 927 | 2,948 |
| 5 | Quality Water And Well Service, Inc. | 208 | 233 | 606 |
| 6 | Sensenig & Weaver Well Drilling Inc. | 197 | 324 | 18,480 |
| 7 | Summit Drilling LLC | 197 | 238 | 1,492 |
| 8 | Eichelbergers Inc. | 180 | 1,066 | 37,074 |
| 9 | Allied Well Drilling | 168 | 274 | 2,213 |
| 10 | C S Garber & Sons Inc. | 149 | 891 | 18,484 |
| 11 | Talon Drilling Company | 140 | 272 | 1,966 |
| 12 | Environmental Probing Investigations Inc. | 139 | 186 | 1,212 |
| 13 | Odyssey Environmental Services, Inc. | 112 | 231 | 7,584 |
| 14 | Bucks County Well Drilling, Inc. | 101 | 2,359 | 3,006 |
| 15 | Todd Mayer's Well Drilling | 85 | 1,605 | 5,307 |
| 16 | Chris Cook - C W Cook, Inc. | 74 | 119 | 274 |
| 17 | East Coast Drilling, Inc. | 65 | 80 | 1,106 |
| 18 | R H Odenheimer Co. | 54 | 399 | 5,276 |
| 19 | Werner & Sons Well Drilling LLC | 37 | 39 | 1,396 |
| 20 | Phares Fry Well Drilling & Pump Svc Inc. | 31 | 212 | 5,909 |
| 21 | Marti Cascade | 29 | 58 | 342 |
| 22 | Parratt-Wolff Inc. | 26 | 35 | 3,500 |
| 23 | Kocher's Water Pumps & Tanks Inc. | 21 | 30 | 2,402 |
| 24 | Mountain Research LLC | 20 | 20 | 1,243 |
| 25 | Alexander Macphee--Cvm Industries | 8 | 97 | 495 |
| 26 | Enviroprobe Service, Inc. | 8 | 34 | 183 |
| 27 | Environmental Field Service Inc. | 8 | 8 | 74 |
| 28 | AC Schultes Inc. | 7 | 11 | 115 |
| 29 | Active Environmental Technologies, Inc. | 7 | 7 | 206 |
| 30 | Petersheim Brothers H20,LLC | 6 | 19 | 8,096 |
| 31 | Myers Brothers Drilling Contr.,Inc. | 6 | 10 | 33,477 |
| 32 | Advanced Drilling Inc. | 6 | 6 | 248 |
| 33 | Powell Drilling And Services | 6 | 6 | 337 |
| 34 | Logan Bollinger | 5 | 141 | 795 |
| 35 | F M & W Drilling Inc. | 5 | 9 | 57 |
| 36 | HD Sonic Drilling, Inc. | 4 | 4 | 728 |
| 37 | Stover's Wells & Pumps, Inc. | 3 | 21 | 29 |
| 38 | Tristate Env. Mgmt. Svcs. Inc. | 3 | 19 | 199 |
| 39 | Mobile Environmental Analytical Inc. | 3 | 3 | 849 |
| 40 | Awt Environmental Services Inc. | 3 | 3 | 111 |
| 41 | Patrick Ferris Company LLC | 3 | 3 | 27 |
| 42 | Duane Moyer Well Drilling | 2 | 10 | 11,486 |
| 43 | Joseph J Guenthoer | 1 | 226 | 248 |
| 44 | Shiffer Drilling, Inc. | 1 | 1 | 904 |
| 45 | Hawk Drilling | 1 | 1 | 480 |
| 46 | Wonsidler Well Drilling Inc. | — | 1,770 | 2,891 |
| 47 | Carson Water Well Inc. | — | 1,256 | 1,749 |
| 48 | Miller Pump Service Inc. | — | 794 | 2,893 |
| 49 | Allen H Dorn | — | 742 | 1,787 |
| 50 | Samuel Y Moyer | — | 637 | 648 |
| 51 | B. L. Myers Bros OF MD,LLC | — | 426 | 12,524 |
| 52 | Walter Leck Well Drilling | — | 78 | 83 |
| 53 | Reith Bros. Inc. | — | 73 | 1,435 |
| 54 | Kerstner Well & Pump Service | — | 71 | 93 |
| 55 | Louis Heintz Well Drilling Inc. | — | 59 | 689 |
| 56 | David Lyman/Samuel Stothoff Co., Inc. | — | 53 | 149 |
| 57 | O B Gill | — | 48 | 55 |
| 58 | Marts Brothers Drilling Inc. | — | 40 | 122 |
| 59 | John Wiley | — | 35 | 37 |
| 60 | Wilmer Shaw | — | 30 | 33 |
| 61 | Handex Consulting & Remediation, LLC | — | 29 | 575 |
| 62 | Norman Cook | — | 28 | 30 |
| 63 | Rulon And Cook Inc. | — | 27 | 68 |
| 64 | Thomas Keyes, Inc. | — | 25 | 5,253 |
| 65 | Austin James Associates, Inc. | — | 25 | 217 |
| 66 | John O'donnell & Son | — | 25 | 43 |
| 67 | Lutz Environmental Co., Inc. | — | 24 | 431 |
| 68 | Walter W Wonsidler | — | 24 | 68 |
| 69 | Arthur Reinheimer Layne Christensen Company | — | 21 | 225 |
| 70 | Water Well Drillers Licensing--Topo Geo | — | 20 | 732 |
| 71 | Ridpath And Potter Company | — | 18 | 249 |
| 72 | William Stothoff Co. Inc. | — | 16 | 70 |
| 73 | Artesian Well Drlg Co. | — | 15 | 144 |
| 74 | Reith Geothermal Energy Inc. | — | 12 | 153 |
| 75 | Phares Fry Well Drilling | — | 11 | 3,694 |
| 76 | John Rulon | — | 11 | 105 |
| 77 | R And R Garber Inc. | — | 8 | 732 |
| 78 | Chesapeake Geosystems Inc. | — | 8 | 54 |
| 79 | Drller Uni-Tech Drilling Co. Inc. | — | 8 | 34 |
| 80 | Tabasco Drilling Corporation | — | 7 | 139 |
| 81 | Sjb Services, Inc. | — | 7 | 44 |
| 82 | IT Environmental Inc. | — | 6 | 131 |
| 83 | A C Schultes & Sons | — | 6 | 38 |
| 84 | Plainfield Well Drilling Co. | — | 5 | 79 |
| 85 | Kohl Bros., Inc. | — | 4 | 2,398 |
| 86 | Chasity Jones | — | 4 | 214 |
| 87 | Raymond E Werner | — | 4 | 195 |
| 88 | M & R Soil Investigations Inc. | — | 4 | 74 |
| 89 | Bellview Pump, LLC | — | 3 | 1,025 |
| 90 | Sepwell Inc. (Yeska) | — | 3 | 811 |
| 91 | Charles Lauman And Son Inc. | — | 3 | 338 |
| 92 | Leidos | — | 3 | 338 |
| 93 | Bassett Environmental Associates, Inc. | — | 3 | 73 |
| 94 | Marcor Environmental Service Inc. | — | 3 | 67 |
| 95 | Environmental Management Associates | — | 3 | 53 |
| 96 | Harrisburg's Kohl Bros Inc. | — | 2 | 2,819 |
| 97 | George J Reed & Son | — | 2 | 423 |
| 98 | Thomas B Harper | — | 2 | 209 |
| 99 | Cook Environmental Services Corporation | — | 2 | 59 |
| 100 | Layne Christensen Company | — | 2 | 44 |
| 101 | Philadelphia Drilling Co. | — | 2 | 42 |
| 102 | Mid-Eastern Geotech Inc. | — | 2 | 38 |
| 103 | Jackson Geothermal Hvac & Drilling LLC | — | 2 | 34 |
| 104 | Dillan Well Drilling Inc. | — | 1 | 4,417 |
| 105 | Alexander's | — | 1 | 3,447 |
| 106 | Knight Well Drilling Inc. | — | 1 | 9,484 |
| 107 | Edward Powell Pump & Well Drilling Inc. | — | 1 | 4,204 |
| 108 | G S Fleese Drillin | — | 1 | 248 |
| 109 | Kodiak Field Services | — | 1 | 1,705 |
| 110 | Robert J Shelhamer | — | 1 | 820 |
| 111 | Greening Drilling Company | — | 1 | 753 |
| 112 | Martin Schafer Jr. Inc. Well Drilling | — | 1 | 593 |
| 113 | R R Hornberger | — | 1 | 508 |
| 114 | Thomas Dunn/Thomas Dunn Well Drilling And Pumps | — | 1 | 456 |
| 115 | Douglas K Reigner | — | 1 | 396 |
| 116 | George L Davis & Sons | — | 1 | 337 |
| 117 | Reeg & Klein Bros | — | 1 | 334 |
| 118 | Carl L Kresge & Sons Inc. | — | 1 | 257 |
| 119 | Thomas Well Drilling | — | 1 | 133 |
| 120 | Joe's Well Drilling | — | 1 | 133 |
| 121 | Floyd O Rapp | — | 1 | 94 |
| 122 | Clayton S Grimm JR | — | 1 | 84 |
| 123 | Peffer Drilling | — | 1 | 72 |
| 124 | Maynard's Pump Service | — | 1 | 68 |
| 125 | Ritzerts | — | 1 | 67 |
| 126 | Quinn & Herron | — | 1 | 36 |
| 127 | Richard E Shonts | — | 1 | 32 |