| 1 | Duane Moyer Well Drilling | 764 | 4,380 | 11,486 |
| 2 | Knight Well Drilling Inc. | 397 | 3,329 | 9,484 |
| 3 | Mobile Environmental Analytical Inc. | 295 | 319 | 849 |
| 4 | Kibler Well Drilling LLC | 202 | 1,383 | 3,255 |
| 5 | Kocher's Water Pumps & Tanks Inc. | 177 | 357 | 2,402 |
| 6 | Werner & Sons Well Drilling LLC | 131 | 249 | 1,396 |
| 7 | Odyssey Environmental Services, Inc. | 45 | 50 | 7,584 |
| 8 | Rumsey Well Drilling LLC | 42 | 668 | 1,974 |
| 9 | Environmental Probing Investigations Inc. | 31 | 32 | 1,212 |
| 10 | C S Garber & Sons Inc. | 27 | 930 | 18,484 |
| 11 | Williams Well Drilling | 27 | 60 | 514 |
| 12 | Labella Environmental, LLC | 25 | 25 | 253 |
| 13 | Bellview Pump, LLC | 23 | 86 | 1,025 |
| 14 | Eichelbergers Inc. | 21 | 199 | 37,074 |
| 15 | Jack Ziegler Well Drilling Inc. | 18 | 672 | 5,789 |
| 16 | Ameridrill, Inc. | 17 | 21 | 5,442 |
| 17 | Advanced Drilling Inc. | 12 | 12 | 248 |
| 18 | Todd Mayer's Well Drilling | 11 | 179 | 5,307 |
| 19 | Tyler Pump And Well Services, LLC | 7 | 7 | 317 |
| 20 | Mayer's Well Drilling | 6 | 190 | 2,948 |
| 21 | Ronald Myers Inc. | 6 | 22 | 3,060 |
| 22 | R H Odenheimer Co. | 5 | 47 | 5,276 |
| 23 | Talon Drilling Company | 5 | 26 | 1,966 |
| 24 | G S Fleese Drillin | 5 | 8 | 248 |
| 25 | Chris Cook - C W Cook, Inc. | 5 | 5 | 274 |
| 26 | Summit Drilling LLC | 4 | 13 | 1,492 |
| 27 | Edward Hook Hook Well Drilling Inc. | 4 | 6 | 471 |
| 28 | David Lyman/Samuel Stothoff Co., Inc. | 3 | 28 | 149 |
| 29 | Parratt-Wolff Inc. | 3 | 21 | 3,500 |
| 30 | Marti Cascade | 3 | 9 | 342 |
| 31 | Enviroprobe Service, Inc. | 3 | 3 | 183 |
| 32 | Cresswell Drilling Co. Inc. | 2 | 4 | 1,525 |
| 33 | Sensenig & Weaver Well Drilling Inc. | 2 | 3 | 18,480 |
| 34 | Phares Fry Well Drilling & Pump Svc Inc. | 1 | 30 | 5,909 |
| 35 | Fritz Bros Inc. | 1 | 17 | 1,424 |
| 36 | Dogan Well Drilling Inc. | — | 1,425 | 1,731 |
| 37 | Myers Drilling Inc. | — | 1,176 | 3,404 |
| 38 | Tomsic Well Drilling | — | 1,109 | 2,232 |
| 39 | Leonard M. Borger Inc. | — | 945 | 2,160 |
| 40 | Gower Well Drilling And Pump Service Inc. | — | 688 | 1,132 |
| 41 | Charles D Moyer | — | 618 | 940 |
| 42 | Leon A Frailey | — | 466 | 503 |
| 43 | Hawk Drilling | — | 450 | 480 |
| 44 | Sepwell Inc. (Yeska) | — | 273 | 811 |
| 45 | Champion Drilling | — | 213 | 514 |
| 46 | R B Smith & Sons Well Drilling | — | 182 | 202 |
| 47 | Barry Frailey | — | 147 | 155 |
| 48 | John J O'rourke Gwd | — | 143 | 199 |
| 49 | Clair T Miller | — | 132 | 133 |
| 50 | William D Krock | — | 115 | 144 |
| 51 | Andrew S Mermon | — | 105 | 756 |
| 52 | Bucks County Well Drilling, Inc. | — | 91 | 3,006 |
| 53 | Austin James Associates, Inc. | — | 88 | 217 |
| 54 | Ralph Neeb Well Drilling | — | 72 | 542 |
| 55 | Joseph Kasmakites | — | 66 | 106 |
| 56 | Hay Well Drilling | — | 64 | 116 |
| 57 | Ernest L Heller | — | 58 | 63 |
| 58 | B. L. Myers Bros OF MD,LLC | — | 57 | 12,524 |
| 59 | Fehr's Well Drilling | — | 52 | 62 |
| 60 | Clair J Miller | — | 52 | 52 |
| 61 | Charles J Tomsic | — | 48 | 95 |
| 62 | Carl L Kresge & Sons Inc. | — | 46 | 257 |
| 63 | Joe's Well Drilling | — | 46 | 133 |
| 64 | Paul E Williams | — | 44 | 50 |
| 65 | Steve S Borger | — | 38 | 126 |
| 66 | Raymond E Kresge | — | 38 | 104 |
| 67 | Kermit K Borger | — | 38 | 43 |
| 68 | Duane M Fehr | — | 33 | 35 |
| 69 | Greening Drilling Company | — | 32 | 753 |
| 70 | Chasity Jones | — | 32 | 214 |
| 71 | Robert Ohl Well Drilling | — | 31 | 718 |
| 72 | Leon L Borger | — | 30 | 95 |
| 73 | Swank & Son Pump Co., Inc. | — | 25 | 1,985 |
| 74 | Water Well Drillers Licensing--Topo Geo | — | 25 | 732 |
| 75 | Christopher Kasa / Casey-Kassa Drilling Co. | — | 16 | 350 |
| 76 | Raymond E Werner | — | 16 | 195 |
| 77 | Martin Schafer Jr. Inc. Well Drilling | — | 14 | 593 |
| 78 | James Bucci | — | 14 | 81 |
| 79 | Reith Bros. Inc. | — | 12 | 1,435 |
| 80 | S. S. Allen | — | 12 | 25 |
| 81 | Lester W Kocher | — | 10 | 278 |
| 82 | Douglas H Steele | — | 10 | 137 |
| 83 | William E Martin | — | 10 | 39 |
| 84 | Leh Val Well & Pump Co. | — | 10 | 38 |
| 85 | Kodiak Field Services | — | 6 | 1,705 |
| 86 | Geo-Environmental Drilling Co. Inc. | — | 6 | 3,228 |
| 87 | Harrisburg's Kohl Bros Inc. | — | 6 | 2,819 |
| 88 | Henry W Kocher | — | 6 | 564 |
| 89 | Robert J Shelhamer | — | 5 | 820 |
| 90 | IT Environmental Inc. | — | 5 | 131 |
| 91 | Richard Frederick | — | 5 | 89 |
| 92 | F E Buehler & Son, Inc. | — | 4 | 2,826 |
| 93 | Greg Sorber Well Drilling, LLC | — | 4 | 127 |
| 94 | Phares Fry Well Drilling | — | 4 | 3,694 |
| 95 | Randler's Well Drilling Inc. | — | 4 | 1,121 |
| 96 | H.w. Kocher Well Drilling Inc. | — | 4 | 172 |
| 97 | Roy G. Kocher's Well Drilling | — | 4 | 66 |
| 98 | Kohl Bros., Inc. | — | 3 | 2,398 |
| 99 | Oscar Dearmit | — | 3 | 2,034 |
| 100 | Tully Drilling Co. Inc. | — | 3 | 1,139 |
| 101 | Ron Mitchell Well Drilling | — | 3 | 422 |
| 102 | William P Shutkufski | — | 3 | 233 |
| 103 | Tyler Well Drilling | — | 3 | 162 |
| 104 | Floyd O Rapp | — | 3 | 94 |
| 105 | Negley's Well Drilling, LLC | — | 2 | 9,098 |
| 106 | Chatfield Drilling, Inc. | — | 2 | 3,589 |
| 107 | Wieand Brothers Well Drilling Inc. | — | 2 | 1,198 |
| 108 | R And R Garber Inc. | — | 2 | 732 |
| 109 | Lutz Environmental Co., Inc. | — | 2 | 431 |
| 110 | Leroy Myers | — | 2 | 319 |
| 111 | H20 Well Drilling T/A | — | 2 | 126 |
| 112 | Bassett Environmental Associates, Inc. | — | 2 | 73 |
| 113 | William Stothoff Co. Inc. | — | 2 | 70 |
| 114 | L Purvis & Son | — | 2 | 49 |
| 115 | Sprague & Henwood Inc. | — | 2 | 25 |
| 116 | Alexander's | — | 1 | 3,447 |
| 117 | Brown Bros Drilling & Service | — | 1 | 5,569 |
| 118 | Thomas Keyes, Inc. | — | 1 | 5,253 |
| 119 | Miller Pump Service Inc. | — | 1 | 2,893 |
| 120 | Bell Bros Well Drl & Water Sys Solns | — | 1 | 2,190 |
| 121 | Moody And Associates, Inc. | — | 1 | 1,117 |
| 122 | Funks Drilling Inc. | — | 1 | 2,469 |
| 123 | Van Fleet Drilling Company Inc. | — | 1 | 1,324 |
| 124 | David Kelly | — | 1 | 135 |
| 125 | James Hubler & Campbell Well Drilling | — | 1 | 133 |
| 126 | K.l. Madron Well Drilling, LLC | — | 1 | 5,980 |
| 127 | Whislers Well Drilling Inc. | — | 1 | 1,819 |
| 128 | George R. Brookover Well Drlg | — | 1 | 1,754 |
| 129 | Carson Water Well Inc. | — | 1 | 1,749 |
| 130 | Snyder Well Drilling Inc. | — | 1 | 1,464 |
| 131 | William T Martin Well Drilling Inc. | — | 1 | 1,108 |
| 132 | Ackerman Drilling | — | 1 | 991 |
| 133 | Lenhart-Stitzel Well Drilling | — | 1 | 772 |
| 134 | Bossard Well Drilling | — | 1 | 716 |
| 135 | George Patterson Well Drilling | — | 1 | 383 |
| 136 | Mummert & Sterner | — | 1 | 301 |
| 137 | Bruce Steele Well Drilling | — | 1 | 301 |
| 138 | Pennsylvania Tectonics, Inc. | — | 1 | 207 |
| 139 | Gayman Well Drilling | — | 1 | 205 |
| 140 | Artesian Well Drlg Co. | — | 1 | 144 |
| 141 | J Normal Connell | — | 1 | 101 |
| 142 | Paul's Well Drilling | — | 1 | 101 |
| 143 | Edsanclay Construction Co. | — | 1 | 97 |
| 144 | Gurvis Gurvis Jones Well Drilling, Inc. | — | 1 | 93 |
| 145 | Edward L Dunlap | — | 1 | 91 |
| 146 | Donald D Piper | — | 1 | 86 |
| 147 | Empire Soils Investigations Inc. | — | 1 | 82 |
| 148 | Bernard Marshall | — | 1 | 75 |
| 149 | E Derau Well Drilling | — | 1 | 72 |
| 150 | J/R Drilling, Ltd (Robert J. Clark) | — | 1 | 47 |
| 151 | Layne Christensen Company | — | 1 | 44 |
| 152 | Sherman E Barber | — | 1 | 38 |
| 153 | Raymond L Butterfield | — | 1 | 36 |