Drilling a New or Replacement Well

Anyone installing a new well—or replacing an inadequate old system needs to plan carefully to ensure an adequate supply of good-quality water.
Drilling a New or Replacement Well - News


Pitless Adaptor. Photo: Bryan Swistock, Penn State University

First, plan your water supply before building your house or drilling your well. Consider the amount of water you need to supply your household and the system needed to supply that amount. The worth of the house and your comfort depend on the water supply you need. Location of the home on the lot may have to be adjusted to suit the well.

A homeowner replacing a well faces a greater challenge. First, locating a place on the property where a sufficient water supply is accessible while also taking into account existing limitations like the location of the septic tank, drainfield or existing structures.

In either case, the location of the well is critical to water quality, including the potential for contamination. Proper location of the water well helps minimize the potential for health risks.

Local drilling contractors generally know about naturally occurring or man-made contamination in area groundwater. The county health department, if there is one, should have information about any health risks related to the groundwater. Many rural counties don't have health departments. You can visit the Penn State Ag Analytical Laboratory "Drinking water test results by county" to learn about problems in your County.

Geology may not be the only factor determining your well location. Surface features such as steep slopes and poorly drained areas will also influence the location of the well and building. If possible, wells should be located at higher elevations than the surrounding areas to decrease the potential for contamination. Well construction is not regulated by any statewide standards in Pennsylvania. Research demonstrates the more construction components are present, the lower the chances of bacterial contamination.

Components of Properly Constructed Well

  • Well casings should be at least 8 inches above the ground or high enough that surface water will never enter the well (even in times of flood).
  • The ground should slope away from the well to prevent surface water from ponding.
  • A pitless adapter should be used where the water pipe passes through the well casing below the frost depth.
  • A sanitary well cap should be used at the top of the casing to prevent insects, small mammals, or other surface contaminants from entering the well.
  • To prevent surface water contamination, the space between the well casing and the drill hole should be filled with a clay grout or cement.

State and local governments have building and zoning regulations governing minimum distances between the wellhead and potential contamination threats. Always research state or local codes or regulations before drilling.

The well is another mechanical system in your home. It should be located so that it is accessible for cleaning, treatment, repair, testing, inspection, and other activities which will be necessary over time.

Here are some general recommendations:

  • Vegetation with deep root systems within 10 feet of the well should be removed
  • Keep the well 100 feet from roadway or driveway; if necessary, mark the well to avoid damage from vehicles or snow removal
  • Wells should be located at least 50 feet from sewers and septic tanks
  • Wells should be at least 100 feet from pastures, on-lot sewage system absorption fields, cesspools and barnyards
  • The wellhead should be at a higher elevation than contamination sources
  • The ground around the wellhead should slope away from the casing

Visit Private Wells for more information.

Adapted from Wellowner.org