Drilled, Driven, or Dug: How to Tell What Kind of Well You Have and How It Gets Water to Your Tap

A residential water well is, at its core, a hole that reaches groundwater plus the equipment that moves that water into your house on demand. The U.S. Environmental Protection Agency and well professionals recognize three basic types of private wells — drilled, driven, and dug — distinguished mainly by how deep they go and how they were built, which in turn drives how vulnerable each is to contamination. Most American homes not served by a public system draw from drilled wells, which reach roughly 100 to 500 feet, according to well-system guides that track residential depths.

Comparative Overview of Residential Well Types

The three well types differ in construction, depth, and contamination risk. A Clemson University Home & Garden Information Center factsheet notes that drilled wells can reach confined aquifers, which tend to carry fewer contaminants than the shallow aquifers the other two types tap — one reason drilled wells are the preferred drinking-water well in South Carolina. Use the table below to match your well's visible features — diameter of the casing, depth, and how it was made — to its likely type. If you are evaluating a property with a large-diameter, stone- or brick-lined opening, you almost certainly have a dug well; a narrow steel pipe sticking up a few feet suggests a drilled or driven well.

Residential well types compared by depth, construction, and contamination susceptibility
Well Type	Typical Depth	Construction Method	Contamination Susceptibility
Drilled	Roughly 100–500 feet for most residential wells	Rotary or percussion drilling rigs penetrate into bedrock; lined with casing	Lowest — depth and casing protect against surface contamination
Driven	Typically 30 to 50 feet	A small-diameter pipe, screened at the bottom, is driven into the ground	Moderate — shallower groundwater is more exposed
Dug	Usually 10 to 30 feet	Hole dug by shovel or backhoe and lined with stone, brick, or tile	Highest — shallow and traditionally lined, offering the least protection

Depth matters for water quality as well as yield. A residential well guide from NightOwl Monitoring, authored by Jim Blair, reports that deep wells at 100 feet and beyond reach more stable, better-protected aquifers, though they require more powerful pumps and cost more to drill. Reliable Home Inspections adds a geological wrinkle worth knowing when you talk to a driller: a drilled well must intersect fractures in the bedrock that actually contain groundwater — depth alone doesn't guarantee a water supply.

Submersible vs. Jet Pumps: Key Differences

Not every well uses a submersible pump, and the alternative shapes both your energy bill and your service experience. Jet pumps sit above ground, typically beside or on top of the well, and pull water up by suction. The depth limit is real: a comparison by Chris Walsh at Benjamin Franklin Plumbing in Clearwater places jet pumps in shallow to moderate wells of roughly up to 120 feet, while submersible pumps handle medium to deep wells of about 120 to 400 feet and beyond, installed underwater inside the casing.

The efficiency gap comes down to physics. Pump-industry explainers note that a jet pump fights gravity and atmospheric pressure to create a vacuum and lift water, an inherently inefficient process, while a submersible pump applies its energy directly to pushing a column of water upward, minimizing losses. Southern California Well Service, a well-service company publishing a pump comparison, estimates submersible pumps run 30 to 50 percent more efficiently, saving $100 to $300 or more annually, and typically last 10 to 15 years — sometimes 20 or more in clean, properly sized installations — versus roughly 4 to 10 years for jet pumps.

That long-term advantage doesn't make the decision automatic. Walsh's comparison gives jet pumps the edge on upfront cost and serviceability: because the motor sits above ground, repairs are easier and cheaper, while a failed submersible must be pulled from the well. Jet pumps are also louder. These figures assume reasonable water quality, correct pump sizing, and a properly matched pressure tank — high sediment, frequent cycling from an undersized tank, or running dry can shorten the life of either type.