| 1 | R H Odenheimer Co. | 393 | 2,444 | 5,276 |
| 2 | Odyssey Environmental Services, Inc. | 165 | 343 | 7,584 |
| 3 | C S Garber & Sons Inc. | 146 | 567 | 18,484 |
| 4 | Kocher's Water Pumps & Tanks Inc. | 145 | 362 | 2,402 |
| 5 | East Coast Drilling, Inc. | 106 | 110 | 1,106 |
| 6 | Mayer's Well Drilling | 105 | 333 | 2,948 |
| 7 | Sensenig & Weaver Well Drilling Inc. | 101 | 267 | 18,480 |
| 8 | Eichelbergers Inc. | 96 | 528 | 37,074 |
| 9 | Phares Fry Well Drilling & Pump Svc Inc. | 77 | 667 | 5,909 |
| 10 | Ameridrill, Inc. | 67 | 140 | 5,442 |
| 11 | Duane Moyer Well Drilling | 43 | 298 | 11,486 |
| 12 | Summit Drilling LLC | 41 | 72 | 1,492 |
| 13 | Werner & Sons Well Drilling LLC | 34 | 51 | 1,396 |
| 14 | Parratt-Wolff Inc. | 23 | 50 | 3,500 |
| 15 | Talon Drilling Company | 22 | 55 | 1,966 |
| 16 | Mobile Environmental Analytical Inc. | 22 | 24 | 849 |
| 17 | Advanced Drilling Inc. | 20 | 20 | 248 |
| 18 | Bellview Pump, LLC | 19 | 202 | 1,025 |
| 19 | Todd Mayer's Well Drilling | 18 | 939 | 5,307 |
| 20 | Allied Well Drilling | 16 | 57 | 2,213 |
| 21 | Myers Brothers Drilling Contr.,Inc. | 12 | 42 | 33,477 |
| 22 | Petersheim Brothers H20,LLC | 11 | 36 | 8,096 |
| 23 | Marti Cascade | 11 | 30 | 342 |
| 24 | Kibler Well Drilling LLC | 11 | 13 | 3,255 |
| 25 | Active Environmental Technologies, Inc. | 11 | 11 | 206 |
| 26 | Ron Mitchell Well Drilling | 10 | 124 | 422 |
| 27 | Mountain Research LLC | 10 | 10 | 1,243 |
| 28 | Chris Cook - C W Cook, Inc. | 8 | 8 | 274 |
| 29 | Environmental Probing Investigations Inc. | 5 | 5 | 1,212 |
| 30 | Knight Well Drilling Inc. | 4 | 4 | 9,484 |
| 31 | Patrick Ferris Company LLC | 4 | 4 | 27 |
| 32 | Miller Pump Service Inc. | 2 | 18 | 2,893 |
| 33 | G S Fleese Drillin | 2 | 4 | 248 |
| 34 | Negley's Well Drilling, LLC | 1 | 2 | 9,098 |
| 35 | Quality Water And Well Service, Inc. | 1 | 1 | 606 |
| 36 | Edward Powell Pump & Well Drilling Inc. | 1 | 1 | 4,204 |
| 37 | Shiffer Drilling, Inc. | 1 | 1 | 904 |
| 38 | Reith Bros. Inc. | — | 780 | 1,435 |
| 39 | Phares Fry Well Drilling | — | 776 | 3,694 |
| 40 | Lenhart-Stitzel Well Drilling | — | 290 | 772 |
| 41 | B. L. Myers Bros OF MD,LLC | — | 261 | 12,524 |
| 42 | Wonsidler Well Drilling Inc. | — | 226 | 2,891 |
| 43 | Henry W Kocher | — | 117 | 564 |
| 44 | Clayton S Grimm JR | — | 36 | 84 |
| 45 | Sepwell Inc. (Yeska) | — | 23 | 811 |
| 46 | Leon L Borger | — | 23 | 95 |
| 47 | Russell Pugh | — | 23 | 32 |
| 48 | Bucks County Well Drilling, Inc. | — | 22 | 3,006 |
| 49 | Lutz Environmental Co., Inc. | — | 22 | 431 |
| 50 | H & M Well Drilling Inc. | — | 20 | 696 |
| 51 | Water Well Drillers Licensing--Topo Geo | — | 19 | 732 |
| 52 | Chasity Jones | — | 19 | 214 |
| 53 | Carson Water Well Inc. | — | 17 | 1,749 |
| 54 | Snyder Well Drilling Inc. | — | 17 | 1,464 |
| 55 | H20 Well Drilling T/A | — | 17 | 126 |
| 56 | Alexander Macphee--Cvm Industries | — | 16 | 495 |
| 57 | Charles Double J Drilling OF W. Va., Inc. | — | 15 | 42 |
| 58 | Leonard M. Borger Inc. | — | 14 | 2,160 |
| 59 | Louis Heintz Well Drilling Inc. | — | 13 | 689 |
| 60 | Leh Val Well & Pump Co. | — | 13 | 38 |
| 61 | Allen H Dorn | — | 12 | 1,787 |
| 62 | E Derau Well Drilling | — | 12 | 72 |
| 63 | R And R Garber Inc. | — | 11 | 732 |
| 64 | AC Schultes Inc. | — | 9 | 115 |
| 65 | Raab Well Drilling, Inc. | — | 7 | 2,909 |
| 66 | Kodiak Field Services | — | 7 | 1,705 |
| 67 | Rumsey Well Drilling LLC | — | 7 | 1,974 |
| 68 | Martin Schafer Jr. Inc. Well Drilling | — | 7 | 593 |
| 69 | Lester W Kocher | — | 7 | 278 |
| 70 | Arnold Drilling LLC | — | 7 | 266 |
| 71 | Charles D Moyer | — | 6 | 940 |
| 72 | Raymond E Werner | — | 6 | 195 |
| 73 | Chesapeake Geosystems Inc. | — | 6 | 54 |
| 74 | Moody And Associates, Inc. | — | 5 | 1,117 |
| 75 | Kohl Bros., Inc. | — | 5 | 2,398 |
| 76 | Ralph Neeb Well Drilling | — | 5 | 542 |
| 77 | Garold L Williams | — | 5 | 25 |
| 78 | Thomas Keyes, Inc. | — | 4 | 5,253 |
| 79 | William W. Reichart, Inc. | — | 4 | 3,242 |
| 80 | Handex Consulting & Remediation, LLC | — | 4 | 575 |
| 81 | Christopher Kasa / Casey-Kassa Drilling Co. | — | 4 | 350 |
| 82 | Aaa Quality Wells & Pumps Inc. | — | 4 | 265 |
| 83 | Cook Environmental Services Corporation | — | 4 | 59 |
| 84 | Paul E Williams | — | 4 | 50 |
| 85 | Andrew S Mermon | — | 3 | 756 |
| 86 | Charles Lauman And Son Inc. | — | 3 | 338 |
| 87 | H.w. Kocher Well Drilling Inc. | — | 3 | 172 |
| 88 | Tabasco Drilling Corporation | — | 3 | 139 |
| 89 | Steve S Borger | — | 3 | 126 |
| 90 | William Stothoff Co. Inc. | — | 3 | 70 |
| 91 | Tristate Env. Mgmt. Svcs. Inc. | — | 2 | 199 |
| 92 | Pennsylvania Drilling Company | — | 2 | 160 |
| 93 | David Kelly | — | 2 | 135 |
| 94 | B L Myers Bros Inc. | — | 2 | 1,232 |
| 95 | Robert Ohl Well Drilling | — | 2 | 718 |
| 96 | Roy G. Kocher's Well Drilling | — | 2 | 66 |
| 97 | Alexander's | — | 1 | 3,447 |
| 98 | Morrison Excavating Morrison Excavating Inc. | — | 1 | 1,160 |
| 99 | George Leib Well Drilling Inc. | — | 1 | 908 |
| 100 | Environmental Field Service Inc. | — | 1 | 74 |
| 101 | Harrisburg's Kohl Bros Inc. | — | 1 | 2,819 |
| 102 | Harry Bros Inc. | — | 1 | 2,237 |
| 103 | Tomsic Well Drilling | — | 1 | 2,232 |
| 104 | Samuel Y Moyer | — | 1 | 648 |
| 105 | Hermann Drilling Co. | — | 1 | 597 |
| 106 | Fisher's Well Drilling | — | 1 | 551 |
| 107 | Gill Enterprises Inc. | — | 1 | 449 |
| 108 | J Karp & Sons, Inc. | — | 1 | 397 |
| 109 | Douglas K Reigner | — | 1 | 396 |
| 110 | Marts Brothers Drilling Inc. | — | 1 | 122 |
| 111 | Kerstner Well & Pump Service | — | 1 | 93 |
| 112 | Mcmichael And Son | — | 1 | 83 |
| 113 | Paul E Kohler | — | 1 | 83 |
| 114 | Mcginnis Drilling | — | 1 | 67 |
| 115 | Chrin OF Delaware, Inc. | — | 1 | 62 |
| 116 | Vircle L Griffin | — | 1 | 61 |
| 117 | Cline & Son Well Drilling | — | 1 | 52 |
| 118 | Layne Christensen Company | — | 1 | 44 |
| 119 | Hand Drilling Co. | — | 1 | 35 |