| A Clean Water Concept | 410-638-9203 | 210 N Tollgate Rd | Bel Air | MD | 21014 |
| Annapolis Irrigation & Sprinkler | 410-315-6943 | 207 Doncaster Rd | Arnold | MD | 21012 |
| Aqua Cool | 410-880-4900 | 8280 Patuxent Range Rd | Jessup | MD | 20794 |
| Aqua-Flo Inc | 410-485-7600 | 6244 Franford Ave | Baltimore | MD | 21206 |
| Bay Shore Labs Inc | 410-221-1159 | 3113 Ocean Gtwy | Cambridge | MD | 21613 |
| Browns Well & Pump Service | 410-437-0237 | 8119 Solley Rd | Pasadena | MD | 21122 |
| Calvert Water Treatment Inc | 410-257-3322 | Box 40 Rt 2 | Owings | MD | 20754 |
| Ceco Utilities Inc | 410-398-5187 | 80 Molitor Rd | Elkton | MD | 21921 |
| Central Water Treatment Co | 410-833-4815 | Carroll Plaza Shopping Center | Westminster | MD | 21136 |
| Chesapeake Irrigation Systems | 410-987-2969 | 405 Headquarters Dr | Millersville | MD | 21108 |
| Chesapeake Labs Inc | 410-546-1318 | 113 High St | Salisbury | MD | 21801 |
| Chesapeake Ranch Water Co | 410-326-4122 | 11560 H G Trueman Rd | Lusby | MD | 20657 |
| Clearwater Design Landscaping | 410-548-1723 | 1416 Bantry Ln | Salisbury | MD | 21801 |
| Clearwater Designs Landscaping | 410-641-4513 | 10534 Assateague Rd | Berlin | MD | 21811 |
| Community Environmental Laboratories | 410-515-6282 | 2023 Emmorton Rd | Fork | MD | 21051 |
| Community Environmental Laboratories | 410-569-2938 | 2023 Emmorton Rd | Bel Air | MD | 21015 |
| Community Environmental Laboratories | 410-569-4694 | 2023 Emmorton Rd | Bel Air | MD | 21015 |
| Curran Environmental | 410-997-0863 | 9325 Our Time Ln | Columbia | MD | 21045 |
| Degrasse George A | 410-798-4469 | 3619 7th Ave | Edgewater | MD | 21037 |
| Delmarva Labs Inc | 410-838-8411 | 260 Gateway Dr | Bel Air | MD | 21014 |
| Denton Spring Water Co | 410-287-0420 | 2411 Theodore Rd | North East | MD | 21901 |
| Eastern Glass Lined Storage | 410-775-2226 | 2040 W Liberty Rd | Westminster | MD | 21157 |
| Eastern Shore Irrigation | 410-208-2739 | 12 E Wind Dr | Berlin | MD | 21811 |
| Eastern Shore Irrigation | 410-778-3584 | 112 Berry Ct | Chestertown | MD | 21620 |
| Environmental Hope | 410-740-5022 | 8808 Centre Park Dr | Columbia | MD | 21045 |
| Envrionmental Testing Lab | 410-643-3303 | Village At Benton S Crsg | Stevensville | MD | 21666 |
| Equinox Independent Representative | 410-964-1167 | 8808 Centre Park Dr | Columbia | MD | 21045 |
| Equinox Independent Representative | 410-992-5535 | 8808 Centre Park Dr | Columbia | MD | 21045 |
| Equinox Independent Representative | 410-995-3843 | 8808 Centre Park Dr | Columbia | MD | 21045 |
| Everpure Drinking Water Systems | 410-744-3400 | 401 Frederick Rd | Catonsville | MD | 21228 |
| Feezer Robert L Co Inc | 410-781-4655 | 6321 Barnett Ave | Sykesville | MD | 21784 |
| Fountain Valley Analytical Laboratory Inc | 410-848-1014 | 1413 Old Taneytown Rd | Westminster | MD | 21158 |
| Grounds Irrigation Technology Inc | 410-923-1200 | 727 Md Rte 3 South | Gambrills | MD | 21032 |
| Hardesty & Son Inc | 410-956-5141 | 3080 Solomons Island Rd | Edgewater | MD | 21037 |
| Health Waters Inc | 410-792-4733 | 10985 Guilford Rd | Annapolis Junction | MD | 20701 |
| Keithly H M Sr Plumbing & Heating | 410-838-1141 | 3007 Snake Ln | Bel Air | MD | 21014 |
| Kyker Dana & Sons Well Driller | 410-848-4170 | 37-1/2 W George St | Westminster | MD | 21157 |
| Kyker Dana & Sons Well Driller | 410-876-1911 | 37-1/2 W George St | Westminster | MD | 21157 |
| Landscape Design Center | 410-956-4140 | 108 Pike Ridge Rd | Edgewater | MD | 21037 |
| Magness Plumbing & Heating Inc | 410-569-0672 | 1502 S Tollgate Rd | Bel Air | MD | 21015 |
| Maryland American Water Co Ofc | 410-838-8403 | 126 S Main St | Bel Air | MD | 21014 |
| Maryland Water Conditioning | 410-792-0327 | 10983 Guilford Rd Ste E | Annapolis Junction | MD | 20701 |
| Mid-Atlantic Plumbing & Water Treatment System | 410-267-7702 | 1752 Mcguckian St | Annapolis | MD | 21401 |
| Mid-Atlantic Watersoft | 410-827-4770 | 6612 Ocean Gtwy # Wye | Queenstown | MD | 21658 |
| Municipal Utilities Commission | 410-228-2955 | Pumping Sta Springfield Ave | Cambridge | MD | 21613 |
| Municipal Utilities Commission Main Ofc | 410-228-5440 | 312 High St | Cambridge | MD | 21613 |
| New World Air & Water Filtratons | 410-327-6306 | 511 S Bond St | Baltimore | MD | 21231 |
| Northeastern Environmental Assessments Inc | 410-287-3121 | 1717 Turkey Point Rd | North East | MD | 21901 |
| Northern Maryland Water | 410-836-0682 | 6 N Main St | Bel Air | MD | 21014 |
| Outside Unlimited Inc | 410-252-3027 | 4195 Saint Paul Rd | Hampstead | MD | 21074 |
| Phelps Edgewater Works | 410-269-0317 | 171 Mayo Rd | Edgewater | MD | 21037 |
| Purner Well Drilling Inc | 410-867-7077 | 983 West Benning Rd | Galesville | MD | 20765 |
| Rands Transport Inc | 410-761-7000 | 7056 Aviation Blvd | Glen Burnie | MD | 21061 |
| Revell Square Water Co Inc | 410-974-4254 | Revell Downs | Annapolis | MD | 21400 |
| Rhoten And Sons | 410-866-3917 | 1100 68th St | Baltimore | MD | 21237 |
| Schagringas Co | 410-398-3400 | 225 S Bridge St | Elkton | MD | 21921 |
| Self-Propelled Irrigation Inc | 410-673-7885 | 7102 East New Market Ellwood Rd | Hurlock | MD | 21643 |
| Snow Valley Water Co | 410-792-7000 | 16200 Branch Ct | Upper Marlboro | MD | 20774 |
| Sunrise Irrigation Inc | 410-882-6446 | 3120 Dubois Ave | Parkville | MD | 21234 |
| Taro Natural Spring Water | 410-531-1438 | 4649 Sheppards Ln | Ellicott City | MD | 21042 |
| Total Lawn Care | 410-749-5296 | 2445 W Zion Rd | Salisbury | MD | 21801 |
| Tri-State Telemarketing Services Inc | 410-679-3133 | 1014 Edgewood Rd | Edgewood | MD | 21040 |
| Twilley Irrigation Systems | 410-742-6961 | 31873 York Dr | Salisbury | MD | 21801 |
| University Micro Reference Laboratory Inc | 410-789-3636 | 611 Hammonds Ferry Rd | Baltimore | MD | 21225 |
| Walsh Francis E Wat | 410-239-3196 | 3232 Shiloh Rd | Hampstead | MD | 21074 |
| Water Testing Laboratories Of Maryland | 410-820-8485 | Rt 50 | Easton | MD | 21606 |
| Water Testing Labs Of Maryland | 410-643-7711 | 1000 Butterworth Ct | Stevensville | MD | 21666 |
