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St. Mary's County, Maryland

Licensed Septic Companies in St. Mary's County, MD

71 septic companies serve St. Mary's County, Maryland, and 71 of them hold a Maryland septic license or certification matched to the Maryland Department of the Environment list (data as of October 2026).

Septic services in St. Mary's County

Guides: Septic tank pumping · Septic system installation · Septic repair · Drain field repair · Aerobic septic systems · Installation cost · Pumping cost

71 septic companies in St. Mary's County

Mechanicsville 21

  • Ark & Dove Excavation, LLC

    40376 Wolfe Dr, Mechanicsville, MD 20659

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 997-6034

  • Buckler Excavating

    26778 Mechanicsville, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-3855

  • C L Boswell Jr Septic

    38170 Laurel Ridge Dr, Mechanicsville, MD 20659

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    From their website: Pumping · Risers & lids Per state license: Installation · Aerobic systems

    (301) 645-9549 clboswelljrseptic.com

  • Darbie & Sons Excavating Inc

    10405 Paramore Pl, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 672-2259

  • David W Griffin

    40727 Colonial Ct, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-1959

  • Eddie Guy Septic

    Po Box 421, Mechanicsville, MD 20659

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    From their website: Pumping · Installation · Repair · Drain field · Perc testing Per state license: Aerobic systems

    (301) 884-3306 eddieguyseptic.com

  • Eugene Copsey Plumbing & Septic

    Po Box 33, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-3239

  • Guy Excavating LLC

    27624 Durango Court/PO Box 746, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-6141

  • Homefirst

    26550 N Sandgates Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 751-5875

  • J. M. Tennyson Construction

    39039 Deer Lane, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-0347

  • Rel Excavating

    27305 Three Notch Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 481-7905

  • Robert A Dave

    29235 New Market Village Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-4165

  • Septic Solutions, LLC

    26439 Morganza Turner Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 997-1000

  • Silver Creek Mechanical Services

    26830 Budds Creek, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (202) 437-7216

  • Silver Creek Mechanical Services

    26830 Budds Creek, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (757) 343-5757

  • Smc Hvac Svc, Inc T/A Southern Md Concrete

    29100 Tye Way, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 399-2312

  • SOMD Septic LLC

    26420 North Sandgates Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (443) 532-8609

  • Stanley L Long

    40255 Stanley La, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-0639

  • Walker Site Maintenance

    29865 Washington Rd, Mechanicsville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 751-1703

  • Wayne'S Drains & Backhoe Service

    27110 Mary Valinda La, Mechanicsville, MD 20609

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-5592 facebook.com

  • Wm Suite Excavating Inc

    26975 Laurel Grove Rd, Mechanicsville, MD 20659

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-4467

Leonardtown 9

  • Downs Plumbing & Septic

    Po Box 2324, Leonardtown, MD 20650

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 997-4080

  • Eagle Excavating & Concrete LLC

    45191 Medley'S Neck Rd, Leonardtown, MD 20650

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-2618

  • Heartwood Homes Ltd

    41540 Singletree Drive, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 538-2902

  • J & W Excavating

    23857 Hollywood, Po Box 381, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 672-6391

  • J Browne Excavating, LLC

    21798 Point Lookout Rd, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 661-5112

  • James Goddard Excavating

    23708 Point Lookout Excavating, Leonardtown, MD 20650

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 475-5313

  • Ronald Delahay

    39980 Stillwater Lane, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 298-0074

  • Southern Md Environmental

    21798 Point Lookout Rd, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 542-7180

  • Southern Md Homes

    22794 Brown Rd, Leonardtown, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 481-8497

Hollywood 8

  • C & C Plumbing

    25765 Three Notch Rd, Hollywood, MD 20636

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 373-2233 ccplumb.com

  • CQI Home Inspections LLC

    42775 Saint Johns Rd, Hollywood, MD 20636

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-1006 cqihomeinspections.com

  • Danny Miedzinski And Son LLC

    24401 Ruff Ruff La, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 373-5315

  • Dome Homes Of Md Inc T/A Crossroads Construction

    Po Box 70, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 373-2109

  • Harris Excavating Solutions LLC

    24790 Cougar Ct, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 561-5711

  • Knolltop Land Management

    42141 Tom Run Ct, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 399-7658

  • Lifelong Renovations

    43610 Lifelong Landing La, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 475-3220

  • Wallys Excavating

    42501 Rive Ridge, Hollywood, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 373-8757

Callaway 6

  • Ab & H Excavating, Inc

    450000 Herman La, Callaway, MD 20620

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-0354 abhexcavating.com

  • AB&H Excavating Inc

    45000 Herman Lance, Callaway, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 925-9585

  • Cullison Excavating LLC

    P.O. Box 156, Callaway, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-1616

  • Cullison Excavating LLC

    Po Box 156, Callaway, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 290-4990

  • Mike Bowes & Sons

    P.O. Box 234, Callaway, MD 20620

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-2429

  • Pete Detempo

    20460 Piney Point Rd, Callaway, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 298-1129

Great Mills 4

  • Duncan Lepper

    Po Box 317, Great Mills, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 256-0200

  • Larry Hills & Sons Excavating Inc

    20531 Point Lookout Rd, Great Mills, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 954-9700

  • Larry Hills & Sons Excavating, Inc

    20531 Point Lookout Rd, Great Mills, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    From their website: Pumping · Repair · Drain field · Perc testing Per state license: Installation · Aerobic systems

    (301) 994-9700 larryhillsandsons.com

  • Larry Hills and Sons Excavating

    20531 Point Lookout rd, Great Mills, MD 20634

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 994-9700 larryhillsandsons.com

California 3

  • Bean'S Excauating And Hauling

    22169 Indian Bridge Road, California, MD 20619

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-5089

  • Feicht Contracting LLC

    23176 Woodland Acres Road, California, MD 20619

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 925-0535

  • Three Notch Construction, LLC

    22589 Three Notch Rd, California, MD 20634

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 862-0000

Clements 3

  • Harry E Farrell Jr

    P. O. Box 271, Clements, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-7294

  • John B Hurry

    24120 Colton Point Rd, Clements, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 538-2942

  • WF Downs Plumbing

    38911 Alice Way, Clements, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 925-0774

Valley Lee 3

  • Carter'S Septic Service

    19244 St George'S Church Rd, Valley Lee, MD 20692

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 298-8619

  • J Brown Excavating LLC

    18670 Windswept La, Valley Lee, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 298-4992

  • Jim'S Custom Homes, Inc

    19272 Vanderhoof Lane, Valley Lee, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-9706

Chaptico 2

  • Cameron Construction Inc

    37837 Grand La, Chaptico, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 884-4624

  • Jimmy Herbert Septic

    23050 Upland Dr, Chaptico, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 769-4380

Dameron 2

  • B-N-B Excavating LLC

    Po Box 71, Dameron, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 538-2437

  • Dameron Contracting

    Po Box137, Dameron, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 904-1668

Lexington Park 2

  • B & D Siteworks, LLC

    20820 Poplar Ridge Rd, Lexington Park, MD 20653

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 925-5093 bdsiteworks.com

  • B & D Siteworks

    47761 Millburn Farm Ln, Lexington Park, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    No phone on the state list

Ridge 2

  • D. B. Plumbing

    49471 Bayne Rd, Ridge, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 481-6871

  • Ridge Construction

    49323 Harry James Rd, Ridge, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 872-4389

Avenue 1

  • A.J Fenwicks Septic LLC

    37790 Paul Ellis Rd, Avenue, MD 20609

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (240) 298-2754

Bryantown 1

  • Superior Tank Inc

    12735 La Platta Rd, Bryantown, MD 20686

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 870-3904

Dickerson 1

  • Downs Excavating Inc

    20800 Beallsville Rd, Dickerson, MD 20626

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 428-8221

Drayden 1

Loveville 1

  • Roy A Williams Construction, LLC

    28931 Point Lookout Rd, Po Box 100, Loveville, MD

    • Licensed: Maryland MDE Certified BAT (Best Available Technology) Septic Installer (Maryland Department of the Environment, verify)

    Per state license: Installation · Aerobic systems

    (301) 672-4467

Lusby 1

Septic licensing in Maryland

Maryland certifies installers of nitrogen-reducing BAT septic units; installers also need the unit maker's certification, and some counties require a local license. The Maryland Department of the Environment issues these credentials: BAT (Best Available Technology) certified installer; County septic installer licenses in some counties.

Permits for new systems, replacements and most repairs are issued locally. Ask the contractor which office handles St. Mary's County and whether the permit fee is in their quote.

Maryland septic licensing: agencies, license types and how to check a license →

Septic companies in St. Mary's County: common questions

How many licensed septic companies are in St. Mary's County, MD?

71 septic companies serve St. Mary's County, Maryland, and 71 of them hold a Maryland septic license or certification matched to the Maryland Department of the Environment list (data as of October 2026). Each license badge on this page names the agency and links to its lookup so you can confirm it.

Who licenses septic contractors in Maryland?

Maryland certifies installers of nitrogen-reducing BAT septic units; installers also need the unit maker's certification, and some counties require a local license. The licensing body is the Maryland Department of the Environment.

Which companies pump septic tanks in St. Mary's County?

3 of the 71 listings in St. Mary's County offer septic tank pumping, either on their own website or under a state pumper license. Use the service filter above to show only those companies.

Which companies install septic systems in St. Mary's County?

71 listings in St. Mary's County install septic systems. New systems and replacements need a permit, so ask each installer to handle the permit and to show their Maryland license.

How do I check a septic contractor's license in Maryland?

Use the Maryland Department of the Environment's lookup (https://mde.maryland.gov/programs/water/BayRestorationFund/OnsiteDisposalSystems/Pages/index.aspx) and search the contractor's name or license number. Our guide to checking a septic license walks through it.