100-Foot Well Drilling Cost

What a 100-foot well actually looks like in 2026

A 100-foot residential well is the answer to a specific geographic question: does the local aquifer produce useful water within the top 100 feet of the surface? In a band of states running from Florida up through the Carolinas, across the Gulf Coast, into the Upper Midwest and parts of the Mississippi alluvial valley, the answer is yes. Outside that band, the answer is usually no, and homeowners drilling shallow because they want the cheaper bid end up with a dry hole or a low-yield well that runs dry in August.

The drilling cost itself is the smallest piece of the bill at this depth. Four hundred feet per hour in sand means a 100-foot bore takes a half-day at most. The cost is dominated by mobilisation (getting the rig to the site and home, $400 to $1,500) and casing (often 100 percent of the bore in unconsolidated material at $10 to $18 per foot). The pump, drop pipe, pressure tank and plumbing-to-house package adds $3,000 to $4,500, which is the same order of magnitude as the drilling itself. That is why the headline "100-foot well costs $3,000" number that gets quoted in old cost guides is misleading: it describes drilling labour and bit time, not what the homeowner actually writes the cheque for.

Cost breakdown line by line for a representative job

Take a 100-foot well in a Wisconsin glacial-deposit area, drilled through 80 feet of sand-and-gravel into the top of a confined aquifer at 80 to 100 feet. Six-inch steel casing is driven the full 100 feet (sand will not stand open), grouted with bentonite from 0 to 20 feet to seal off surface water. A 0.75 HP submersible pump is set at 90 feet on plastic drop pipe with a control box at the wellhead. A 32-gallon pressure tank is plumbed into the basement, fed by a 200-foot trench from well to house.

Line items at typical 2026 rates. Mobilisation $600. Drilling 100 feet at $30 per foot through sand-and-gravel, $3,000. Six-inch steel casing 100 feet at $14 per foot, $1,400. Bentonite grouting 20 feet, $250. Stainless-steel well screen at the bottom of the casing, $300. Well cap with vent and pitless adapter, $250. Development (surging and pumping until clear) 3 hours, $360. Submersible pump 0.75 HP with control box, $1,100. Drop pipe and electrical 90 feet, $400. Pressure tank 32 gallon with switch and fittings, $550. Trench from well to house (200 ft of PEX), $750. Permit and water test $250. Subtotal: $9,210. With 10 percent contingency, $10,131. That is a fair middle-of-the-range bid for this scope in 2026.

Where the per-foot rate sits at 100 feet

Per-foot rates at this depth tend to absorb the rig mobilisation, which means they are slightly elevated relative to the drilling-only rate quoted in our cost-per-foot reference. A driller who quotes $30 per foot on a 100-foot job in sand is including roughly $5 per foot of amortised setup; on a 300-foot job the same driller would quote $25 per foot for the same geology because the mobilisation spreads over more bore. Expect the all-in 100-foot rate to land $25 to $35 in sand-and-gravel, $32 to $45 in clay or soft sedimentary rock, and $42 to $60 in the rare hard-rock 100-foot well (hard rock at this depth usually means the homeowner could drill 50 feet shallower or 200 feet deeper for the same money).

Regions where 100-foot wells are standard

Florida. The Floridan and Biscayne aquifers sit between 50 and 200 feet across most of the state. Sandy coastal-plain soils mean drilling is fast and cheap; FDEP sets construction standards that are easily met. A 100-foot well in central Florida runs $3,500 to $7,000 installed, near the cheapest in the country. Watch for saltwater-intrusion zones on the coast where the deeper Floridan is preferred over the shallower Biscayne.

Upper Midwest (MI, WI, MN). Glacial outwash deposits and shallow buried-valley aquifers produce strong yield in the top 50 to 150 feet. Sandy soils drill quickly; the limiting factor is often the need for full-length casing through the unconsolidated material. A 100-foot well in Michigan or Wisconsin typically runs $6,000 to $11,000 installed, slightly more than Florida because of the heavier casing requirement.

Mississippi alluvial valley. The shallow alluvial aquifer in eastern Arkansas, the Mississippi Delta and the Missouri Bootheel sits at 50 to 150 feet and is heavily used for both rural-residential and agricultural irrigation. Residential 100-foot wells here run $5,000 to $9,000 installed; agricultural wells of similar depth but 8 to 12 inch casing run substantially more (see agricultural irrigation well cost).

Coastal Carolinas. The Castle Hayne and Black Creek aquifers across coastal NC and SC support 100-foot residential wells. Sandy soils, fast drilling, similar pricing to Florida.

Regions where 100 feet is too shallow

Across New England, the Adirondacks, the southern Appalachian mountains, most of the interior West and the Pacific Northwest highlands, 100 feet rarely produces a reliable residential well. The water table is too deep, the bedrock aquifers begin only at 150 to 400 feet, or seasonal variation is so large that a 100-foot well runs dry in late summer. Homeowners in these regions who get a 100-foot bid on a vacation cabin or weekend property should ask the driller for written justification (local well logs, area depth-to-water data) before signing. Drilling to 100 feet and capping off a dry hole still costs $4,000 to $7,000 with no water at the end of it.

The USGS groundwater overview and Ground Water Atlas of the United States are the right starting points to confirm whether your county has shallow productive aquifers. State geological surveys publish more detailed well-log databases that show actual completion depths within five miles of any address; ask the driller for theirs or pull the records yourself before committing to a shallow depth target.

Pump choice at 100 feet

The pump decision is the second-biggest cost lever after the drilling itself. Two options work at this depth, with different price-and-noise tradeoffs.

Submersible (in-well) pump. A 0.5 to 0.75 HP submersible drops down the casing on a length of drop pipe, with the wiring run through a watertight splice at the wellhead. Pump cost $700 to $1,400; installation $600 to $1,200. Quiet (no above-ground noise), efficient at this depth, long service life (10 to 20 years before replacement). The standard choice for a 100-foot residential well. Pump replacement requires pulling the drop pipe, which is a half-day job and $1,500 to $2,500 in labour at this depth.

Shallow-well jet pump. A small (0.5 to 0.75 HP) above-ground centrifugal pump uses suction lift through a 1.25 inch foot valve at the bottom of the well. Pump cost $300 to $700; installation $400 to $900. Cheaper to buy, much easier to service (it sits in the basement or well house), but it is noisier and loses efficiency rapidly below 25 feet of standing water (the suction-lift physical limit is ~25 feet at sea level). Recommended only when the static water level is within 20 feet of the surface, which is rare even at this depth.

See pump installation costs for the full pump-type comparison.

Why some 100-foot wells fail

Three failure modes account for most early-life problems on shallow wells. Surface contamination from poor grouting is the most common: bentonite that was not properly hydrated, or grouted only to 10 feet when the local code requires 20, lets surface water track down the outside of the casing into the producing zone. Coliform-positive water samples in the first year are the classic symptom; the fix is regrouting at $400 to $1,000 if catchable, or full abandonment and re-drill if the contamination is established.

Seasonal yield collapse is the second mode. A 100-foot well that produces 8 gpm in May may produce 2 gpm in September if the local water table drops 15 feet in the dry season. Wells drilled in wet years to a depth that "looked fine" routinely under-perform in the third or fourth dry summer. The mitigation is to deepen at $30 to $50 per foot of additional bore or to add storage (a 1,000 gallon pressurised cistern at $1,500 to $3,000 buys a week of household water at low yield).

The third mode is iron and manganese staining, which is common in shallow alluvial aquifers (Mississippi, Missouri, Ohio valleys). The water is safe but stains fixtures and laundry; a water-softener and oxidising filter setup at $1,500 to $3,500 is the standard fix. Worth budgeting for upfront if your county has a known iron-rich aquifer.

Cross-references and adjacent depths

For the per-foot rate breakdown that underlies the drilling cost above, see well drilling cost per foot 2026. For the next depth up, see 200-foot well drilling cost. For the casing component priced separately, well casing cost. For state-specific pricing, Florida well drilling cost is the cheapest 100-foot-well state in the country, while cost by state covers the rest. If your bore comes in dry, see well hydrofracturing and well deepening vs new well.