| 1 | Kocher's Water Pumps & Tanks Inc. | 427 | 1,116 | 2,402 |
| 2 | Werner & Sons Well Drilling LLC | 235 | 858 | 1,396 |
| 3 | R H Odenheimer Co. | 138 | 1,324 | 5,276 |
| 4 | Eichelbergers Inc. | 133 | 504 | 37,074 |
| 5 | Sensenig & Weaver Well Drilling Inc. | 109 | 170 | 18,480 |
| 6 | Odyssey Environmental Services, Inc. | 78 | 108 | 7,584 |
| 7 | Rumsey Well Drilling LLC | 70 | 881 | 1,974 |
| 8 | C S Garber & Sons Inc. | 63 | 504 | 18,484 |
| 9 | Mobile Environmental Analytical Inc. | 62 | 67 | 849 |
| 10 | Duane Moyer Well Drilling | 37 | 274 | 11,486 |
| 11 | Raab Well Drilling, Inc. | 35 | 41 | 2,909 |
| 12 | Talon Drilling Company | 34 | 68 | 1,966 |
| 13 | Bellview Pump, LLC | 30 | 386 | 1,025 |
| 14 | Mayer's Well Drilling | 27 | 270 | 2,948 |
| 15 | Ameridrill, Inc. | 25 | 122 | 5,442 |
| 16 | East Coast Drilling, Inc. | 19 | 20 | 1,106 |
| 17 | Phares Fry Well Drilling & Pump Svc Inc. | 18 | 249 | 5,909 |
| 18 | Summit Drilling LLC | 18 | 71 | 1,492 |
| 19 | Kibler Well Drilling LLC | 14 | 23 | 3,255 |
| 20 | Todd Mayer's Well Drilling | 12 | 415 | 5,307 |
| 21 | Knight Well Drilling Inc. | 11 | 36 | 9,484 |
| 22 | Environmental Probing Investigations Inc. | 10 | 13 | 1,212 |
| 23 | Parratt-Wolff Inc. | 9 | 21 | 3,500 |
| 24 | Allied Well Drilling | 9 | 18 | 2,213 |
| 25 | F E Buehler & Son, Inc. | 9 | 16 | 2,826 |
| 26 | Enviroprobe Service, Inc. | 6 | 6 | 183 |
| 27 | Mountain Research LLC | 5 | 5 | 1,243 |
| 28 | Reith Geothermal Energy Inc. | 4 | 5 | 153 |
| 29 | Chris Cook - C W Cook, Inc. | 4 | 4 | 274 |
| 30 | Negley's Well Drilling, LLC | 3 | 4 | 9,098 |
| 31 | Tyler Pump And Well Services, LLC | 3 | 3 | 317 |
| 32 | Ron Mitchell Well Drilling | 2 | 141 | 422 |
| 33 | Advanced Drilling Inc. | 2 | 10 | 248 |
| 34 | Cresswell Drilling Co. Inc. | 2 | 4 | 1,525 |
| 35 | Petersheim Brothers H20,LLC | 2 | 2 | 8,096 |
| 36 | Bucks County Well Drilling, Inc. | 1 | 121 | 3,006 |
| 37 | David Lyman/Samuel Stothoff Co., Inc. | 1 | 4 | 149 |
| 38 | Patrick Ferris Company LLC | 1 | 1 | 27 |
| 39 | Henry W Kocher | — | 436 | 564 |
| 40 | Sepwell Inc. (Yeska) | — | 409 | 811 |
| 41 | Tomsic Well Drilling | — | 284 | 2,232 |
| 42 | Lester W Kocher | — | 184 | 278 |
| 43 | Raymond E Werner | — | 166 | 195 |
| 44 | B. L. Myers Bros OF MD,LLC | — | 145 | 12,524 |
| 45 | Floyd O Rapp | — | 90 | 94 |
| 46 | H.w. Kocher Well Drilling Inc. | — | 81 | 172 |
| 47 | H20 Well Drilling T/A | — | 78 | 126 |
| 48 | Leonard M. Borger Inc. | — | 66 | 2,160 |
| 49 | Reith Bros. Inc. | — | 63 | 1,435 |
| 50 | Wonsidler Well Drilling Inc. | — | 58 | 2,891 |
| 51 | Phares Fry Well Drilling | — | 48 | 3,694 |
| 52 | J/R Drilling, Ltd (Robert J. Clark) | — | 46 | 47 |
| 53 | Chrin OF Delaware, Inc. | — | 44 | 62 |
| 54 | William W. Reichart, Inc. | — | 43 | 3,242 |
| 55 | Roy G. Kocher's Well Drilling | — | 42 | 66 |
| 56 | E Derau Well Drilling | — | 40 | 72 |
| 57 | Charles J Tomsic | — | 39 | 95 |
| 58 | Joseph Kasmakites | — | 36 | 106 |
| 59 | Joe's Well Drilling | — | 28 | 133 |
| 60 | Kerstner Well & Pump Service | — | 20 | 93 |
| 61 | Martin Schafer Jr. Inc. Well Drilling | — | 18 | 593 |
| 62 | Dan Burgess Well Drilling | — | 17 | 392 |
| 63 | Empire Soils Investigations Inc. | — | 15 | 82 |
| 64 | Arnold Drilling LLC | — | 14 | 266 |
| 65 | Clayton S Grimm JR | — | 13 | 84 |
| 66 | Bassett Environmental Associates, Inc. | — | 13 | 73 |
| 67 | Mcginnis Drilling | — | 13 | 67 |
| 68 | Dms Environmental Services, LLC | — | 12 | 670 |
| 69 | Alexander Macphee--Cvm Industries | — | 12 | 495 |
| 70 | Carson Water Well Inc. | — | 12 | 1,749 |
| 71 | Charles D Moyer | — | 12 | 940 |
| 72 | J E Fritts & Associates Incorporated | — | 12 | 51 |
| 73 | S. S. Allen | — | 11 | 25 |
| 74 | Dogan Well Drilling Inc. | — | 10 | 1,731 |
| 75 | Lenhart-Stitzel Well Drilling | — | 10 | 772 |
| 76 | R And R Garber Inc. | — | 9 | 732 |
| 77 | Miller Pump Service Inc. | — | 8 | 2,893 |
| 78 | Allen H Dorn | — | 8 | 1,787 |
| 79 | Myers Drilling Inc. | — | 7 | 3,404 |
| 80 | Lutz Environmental Co., Inc. | — | 7 | 431 |
| 81 | Leon L Borger | — | 7 | 95 |
| 82 | Russell Pugh | — | 7 | 32 |
| 83 | Robert Ohl Well Drilling | — | 6 | 718 |
| 84 | William Stothoff Co. Inc. | — | 6 | 70 |
| 85 | Leh Val Well & Pump Co. | — | 6 | 38 |
| 86 | Andrew S Mermon | — | 5 | 756 |
| 87 | Fisher's Well Drilling | — | 5 | 551 |
| 88 | G S Fleese Drillin | — | 4 | 248 |
| 89 | Arthur Reinheimer Layne Christensen Company | — | 4 | 225 |
| 90 | Steve S Borger | — | 4 | 126 |
| 91 | Gill Rock Drill Co. Inc. | — | 4 | 114 |
| 92 | Jack Ziegler Well Drilling Inc. | — | 3 | 5,789 |
| 93 | Water Well Drillers Licensing--Topo Geo | — | 3 | 732 |
| 94 | Ralph Neeb Well Drilling | — | 3 | 542 |
| 95 | Carl L Kresge & Sons Inc. | — | 3 | 257 |
| 96 | Myers Brothers Drilling Contr.,Inc. | — | 2 | 33,477 |
| 97 | Edward Powell Pump & Well Drilling Inc. | — | 2 | 4,204 |
| 98 | HD Sonic Drilling, Inc. | — | 2 | 728 |
| 99 | Kuser Well Drilling | — | 2 | 648 |
| 100 | Logan Bollinger | — | 2 | 795 |
| 101 | Greening Drilling Company | — | 2 | 753 |
| 102 | H & M Well Drilling Inc. | — | 2 | 696 |
| 103 | Samuel Y Moyer | — | 2 | 648 |
| 104 | L G Hetager Drilling Inc. | — | 2 | 600 |
| 105 | William D Krock | — | 2 | 144 |
| 106 | Carl Traugher | — | 2 | 137 |
| 107 | Marts Brothers Drilling Inc. | — | 2 | 122 |
| 108 | James Bucci | — | 2 | 81 |
| 109 | Thomas Keyes, Inc. | — | 1 | 5,253 |
| 110 | Swank & Son Pump Co., Inc. | — | 1 | 1,985 |
| 111 | Williams Well Drilling | — | 1 | 514 |
| 112 | Harrisburg's Kohl Bros Inc. | — | 1 | 2,819 |
| 113 | Kohl Bros., Inc. | — | 1 | 2,398 |
| 114 | Duane Cizek | — | 1 | 1,894 |
| 115 | William T Martin Well Drilling Inc. | — | 1 | 1,108 |
| 116 | Leroy Myers | — | 1 | 319 |
| 117 | Chasity Jones | — | 1 | 214 |
| 118 | Thomas B Harper | — | 1 | 209 |
| 119 | John J O'rourke Gwd | — | 1 | 199 |
| 120 | Barry Frailey | — | 1 | 155 |
| 121 | Gurvis Gurvis Jones Well Drilling, Inc. | — | 1 | 93 |
| 122 | Groundwater Technology | — | 1 | 75 |
| 123 | Layne Christensen Company | — | 1 | 44 |
| 124 | Philadelphia Drilling Co. | — | 1 | 42 |
| 125 | Wilmer Shaw | — | 1 | 33 |