| 1 | C S Garber & Sons Inc. | 599 | 4,752 | 18,484 |
| 2 | Ameridrill, Inc. | 452 | 852 | 5,442 |
| 3 | Sensenig & Weaver Well Drilling Inc. | 391 | 1,002 | 18,480 |
| 4 | Quality Water And Well Service, Inc. | 343 | 372 | 606 |
| 5 | Eichelbergers Inc. | 314 | 1,437 | 37,074 |
| 6 | Environmental Probing Investigations Inc. | 217 | 264 | 1,212 |
| 7 | Mayer's Well Drilling | 189 | 706 | 2,948 |
| 8 | Odyssey Environmental Services, Inc. | 185 | 346 | 7,584 |
| 9 | Allied Well Drilling | 160 | 387 | 2,213 |
| 10 | Edward Powell Pump & Well Drilling Inc. | 100 | 391 | 4,204 |
| 11 | Summit Drilling LLC | 91 | 228 | 1,492 |
| 12 | Raab Well Drilling, Inc. | 76 | 297 | 2,909 |
| 13 | East Coast Drilling, Inc. | 70 | 98 | 1,106 |
| 14 | Parratt-Wolff Inc. | 68 | 107 | 3,500 |
| 15 | Thomas Keyes, Inc. | 60 | 385 | 5,253 |
| 16 | Talon Drilling Company | 52 | 476 | 1,966 |
| 17 | Miller Pump Service Inc. | 40 | 1,541 | 2,893 |
| 18 | Todd Mayer's Well Drilling | 40 | 970 | 5,307 |
| 19 | Tristate Env. Mgmt. Svcs. Inc. | 34 | 64 | 199 |
| 20 | Chris Cook - C W Cook, Inc. | 32 | 54 | 274 |
| 21 | Powell Drilling And Services | 30 | 39 | 337 |
| 22 | Phares Fry Well Drilling & Pump Svc Inc. | 28 | 123 | 5,909 |
| 23 | F E Buehler & Son, Inc. | 27 | 134 | 2,826 |
| 24 | Active Environmental Technologies, Inc. | 21 | 21 | 206 |
| 25 | Enviroprobe Service, Inc. | 20 | 34 | 183 |
| 26 | Logan Bollinger | 16 | 539 | 795 |
| 27 | Myers Brothers Drilling Contr.,Inc. | 15 | 66 | 33,477 |
| 28 | Petersheim Brothers H20,LLC | 12 | 144 | 8,096 |
| 29 | Advanced Drilling Inc. | 12 | 24 | 248 |
| 30 | R H Odenheimer Co. | 11 | 30 | 5,276 |
| 31 | Mountain Research LLC | 11 | 21 | 1,243 |
| 32 | HD Sonic Drilling, Inc. | 11 | 11 | 728 |
| 33 | Bucks County Well Drilling, Inc. | 10 | 133 | 3,006 |
| 34 | Morrison Excavating Morrison Excavating Inc. | 10 | 14 | 1,160 |
| 35 | Environmental Field Service Inc. | 9 | 17 | 74 |
| 36 | Awt Environmental Services Inc. | 8 | 8 | 111 |
| 37 | Patrick Ferris Company LLC | 5 | 5 | 27 |
| 38 | Reith Geothermal Energy Inc. | 4 | 129 | 153 |
| 39 | Werner & Sons Well Drilling LLC | 4 | 4 | 1,396 |
| 40 | Dms Environmental Services, LLC | 4 | 4 | 670 |
| 41 | F M & W Drilling Inc. | 3 | 18 | 57 |
| 42 | Duane Moyer Well Drilling | 2 | 16 | 11,486 |
| 43 | K.l. Madron Well Drilling, LLC | 2 | 10 | 5,980 |
| 44 | Marti Cascade | 2 | 2 | 342 |
| 45 | B. L. Myers Bros OF MD,LLC | 1 | 1,372 | 12,524 |
| 46 | Alexander Macphee--Cvm Industries | 1 | 156 | 495 |
| 47 | Kocher's Water Pumps & Tanks Inc. | 1 | 7 | 2,402 |
| 48 | Negley's Well Drilling, LLC | 1 | 4 | 9,098 |
| 49 | Ritchey Well Drilling | 1 | 2 | 1,675 |
| 50 | Allen H Dorn | — | 924 | 1,787 |
| 51 | Wonsidler Well Drilling Inc. | — | 554 | 2,891 |
| 52 | Louis Heintz Well Drilling Inc. | — | 467 | 689 |
| 53 | Michael Kuszyk | — | 371 | 652 |
| 54 | R And R Garber Inc. | — | 222 | 732 |
| 55 | Charles Lauman And Son Inc. | — | 222 | 338 |
| 56 | Lutz Environmental Co., Inc. | — | 219 | 431 |
| 57 | Douglas K Reigner | — | 195 | 396 |
| 58 | Water Well Drillers Licensing--Topo Geo | — | 162 | 732 |
| 59 | Carson Water Well Inc. | — | 112 | 1,749 |
| 60 | Phares Fry Well Drilling | — | 73 | 3,694 |
| 61 | Ridpath And Potter Company | — | 63 | 249 |
| 62 | Handex Consulting & Remediation, LLC | — | 48 | 575 |
| 63 | Tabasco Drilling Corporation | — | 48 | 139 |
| 64 | Funks Drilling Inc. | — | 41 | 2,469 |
| 65 | Aaa Quality Wells & Pumps Inc. | — | 41 | 265 |
| 66 | Kohl Bros., Inc. | — | 40 | 2,398 |
| 67 | Walter W Wonsidler | — | 34 | 68 |
| 68 | M & R Soil Investigations Inc. | — | 31 | 74 |
| 69 | Plainfield Well Drilling Co. | — | 29 | 79 |
| 70 | AC Schultes Inc. | — | 25 | 115 |
| 71 | IT Environmental Inc. | — | 24 | 131 |
| 72 | Chesapeake Geosystems Inc. | — | 22 | 54 |
| 73 | Reith Bros. Inc. | — | 21 | 1,435 |
| 74 | Empire Soils Investigations Inc. | — | 20 | 82 |
| 75 | Arnold Drilling LLC | — | 18 | 266 |
| 76 | Chasity Jones | — | 18 | 214 |
| 77 | Cook Environmental Services Corporation | — | 18 | 59 |
| 78 | John O'donnell & Son | — | 17 | 43 |
| 79 | George R. Brookover Well Drlg | — | 16 | 1,754 |
| 80 | William Stothoff Co. Inc. | — | 15 | 70 |
| 81 | David Lyman/Samuel Stothoff Co., Inc. | — | 14 | 149 |
| 82 | Philadelphia Drilling Co. | — | 14 | 42 |
| 83 | Environmental Management Associates | — | 13 | 53 |
| 84 | Joseph J Guenthoer | — | 12 | 248 |
| 85 | Kodiak Field Services | — | 10 | 1,705 |
| 86 | Marcor Environmental Service Inc. | — | 10 | 67 |
| 87 | J E Fritts & Associates Incorporated | — | 10 | 51 |
| 88 | William W. Reichart, Inc. | — | 9 | 3,242 |
| 89 | Rulon And Cook Inc. | — | 9 | 68 |
| 90 | Hawk Drilling | — | 8 | 480 |
| 91 | B L Myers Bros Inc. | — | 8 | 1,232 |
| 92 | Thomas B Harper | — | 8 | 209 |
| 93 | Cds/Division Layne W. Company Incorp | — | 8 | 26 |
| 94 | Samuel Y Moyer | — | 7 | 648 |
| 95 | L G Hetager Drilling Inc. | — | 7 | 600 |
| 96 | Layne Christensen Company | — | 7 | 44 |
| 97 | Drller Uni-Tech Drilling Co. Inc. | — | 7 | 34 |
| 98 | Michael Kavlunas Total Quality Drilling, LLC | — | 6 | 49 |
| 99 | Pennsylvania Drilling Company | — | 6 | 160 |
| 100 | Mcginnis Drilling | — | 6 | 67 |
| 101 | A C Schultes & Sons | — | 6 | 38 |
| 102 | MB Drilling LLC | — | 6 | 35 |
| 103 | Artesian Well Drlg Co. | — | 5 | 144 |
| 104 | Walter Leck Well Drilling | — | 5 | 83 |
| 105 | Jackson Geothermal Hvac & Drilling LLC | — | 5 | 34 |
| 106 | Moody And Associates, Inc. | — | 4 | 1,117 |
| 107 | Arthur Reinheimer Layne Christensen Company | — | 4 | 225 |
| 108 | Groundwater Technology | — | 4 | 75 |
| 109 | Keller Industrial, Inc. | — | 4 | 56 |
| 110 | Gill Enterprises Inc. | — | 3 | 449 |
| 111 | Mac Flow Water Well Systems Inc. | — | 3 | 148 |
| 112 | Marts Brothers Drilling Inc. | — | 3 | 122 |
| 113 | Snyder Well Drilling Inc. | — | 2 | 1,464 |
| 114 | Sjb Services, Inc. | — | 2 | 44 |
| 115 | John Wiley | — | 2 | 37 |
| 116 | R A Kessinger | — | 2 | 35 |
| 117 | Wilmer Shaw | — | 2 | 33 |
| 118 | Toy Drilling Co. Inc. | — | 1 | 1,343 |
| 119 | John Thran | — | 1 | 2,266 |
| 120 | Charles D Moyer | — | 1 | 940 |
| 121 | H & M Well Drilling Inc. | — | 1 | 696 |
| 122 | Henry W Kocher | — | 1 | 564 |
| 123 | Anderson Well Drilling & Pump Sales | — | 1 | 486 |
| 124 | George J Reed & Son | — | 1 | 423 |
| 125 | J Karp & Sons, Inc. | — | 1 | 397 |
| 126 | Potts Drilling | — | 1 | 225 |
| 127 | Richard H Stanley | — | 1 | 200 |
| 128 | John Rulon | — | 1 | 105 |
| 129 | Clayton S Grimm JR | — | 1 | 84 |
| 130 | Dave Carner Trades | — | 1 | 80 |
| 131 | David Leonard Water Well Drilling Co. | — | 1 | 60 |
| 132 | John J Koren & Sons | — | 1 | 56 |
| 133 | C & V Drilling | — | 1 | 41 |