Denis L. Maher Logo

In 2023, Weston & Sampson acquired Denis L. Maher Co. to expand our existing Water practice. With this enhanced capacity, we can continue to deliver innovative well drilling and pump services to an expanded footprint of clients.

Our services include Well Drilling, Gravel Packed Wells, Gravel Developed Wells, Cleaning and Rehabilitation of Wells, Geotechnical Support, Hydrogeologic Assessments, Pump Sales, Pump Services and Pump Maintenance. Our primary markets are Municipal, Recreational, Industrial, Golf Course and Irrigation applications.

With our dedicated staff of highly trained and experienced experts in the field, we are a recognized leader in the industry. We sincerely look forward to putting the benefits of our knowledge and dedication to superior service to work for you.

Municipal, Industrial & Irrigation Services

Well Drilling & Related

  • Test Wells, Exploratory Programs & Related Hydrogeologic Assessments
  • Gravel Packed High Capacity Wells: Gravel Developed Medium to High Yield Wells
  • Tubular Well Fields
  • Evaluation of Existing Ground Water Supplies

Well Maintenance & Related

  • Emergency Response 24/7
  • Specific Capacity Test on Existing Wells
  • Video Inspection
  • Well Redevelopment: Conventional using Chemicals
    Well Redevelopment: Using a Combination of Methods
  • Well Relining, Rescreening, Repacking, Repair & Replacement of Old or Damaged Wells

Pumps & Related

  • Emergency Response 24/7
  • Sales & Services
  • Removal & Repair of Vertical Turbine Pumps including Line Shaft & Submersible
  • Well Pumps
  • Water Treatment Plant Pumps
  • Horizontal Split Case Pumps
  • Horizontal End Suction Pumps
  • Process Pumps
  • Booster Pumps
  • Right Angle Gear Drives
  • Vertical Hollow Shaft, Vertical Solid Shaft & Horizontal Motors of all Makes
  • Preventative Maintenance Testing & Service of Existing Installations

Denis L. Maher Sr.


Founded in 1941 by Denis L. Maher Sr. the D. L. Maher Co. quickly became recognized as a leader in the Well Drilling and Pump Services industry. After several years of different ownership and management, Denis L. Maher Jr. came out of retirement and was at the helm of the newly formed Denis L. Maher Co.

Denis L. Maher Jr.'s expertise in the business was achieved by working alongside his father, and over the years has advanced his knowledge of the business to a level where he is qualified to instruct others in the correct operation, repair and management of wells and pumps. Among other accomplishments and recognitions by the industry, he has served as the Chairman of the New England and American Water Works Association's Standards Committee on Vertical Turbine Pumps for a period of 13 years, and helped to develop and implement the standards that are in use today.


Where is the best place to locate a well on my property?

The Geology of the land will determine the best place to locate a well on any given property.

I need X number of gallons per minute. What is the right well for me?

The geology of the site will determine the correct type of well to consider. In some areas permeable sediments were left by the retreating glacier. If saturated they may yield sufficient water to meet your demand. Because the underlying bedrock, for most of New England, is not porous rock wells can hit or miss. However, fracture trace and lineament mapping may identify zones of fractured rock where ground water may be stored and can move rapidly. A well drilled at the convergence of several fractures can produce large volumes of water. We offer hydrogeologic assesments of which type of well may be most appropriate for you.

My well is not pumping what it is supposed to. What is the best way to clean it?

The best way to clean a well is determined by first understanding why the yield has diminished. Several possibilities are:

    • Overpumping has dewatered the aquifer, thereby lowering the water table.
    • Oxides of iron and manganese are clogging the well screen, pack and/or native formation.
    • Bioslimes or bacteria may retard flow.
    • Fine sand or clay may be migrating into the native formation or pack.
    • The pump may be worn.

When we know why the yield has fallen off, then a number of procedures for physical agitation and chemical introduction are available.

Can a high yielding rock well be developed in New England?

Although we have very little sandstone or limestone in our region the technique of fracture trace and lineament mapping can help find areas of promise.

My well pump runs but the well no longer produces water. What are some possible causes for this condition?
    • The pump may be broken.
    • The pump may be plugged.

If you would like further information about D. L. Maher or wish to discuss a project with us, please call, email or schedule a visit to our office.

16 Legate Hill Road • Sterling, MA 01564

Tel: (978) 615-4606





Contact us today for a quote or assistance with your water needs