What Is The Difference Between A Dug Well And A Drilled Well?

Are you deciding whether a property with a well is right for you and want to understand the key differences before you commit?

What Is The Difference Between A Dug Well And A Drilled Well?

Choosing a home with a private water source can feel overwhelming, but understanding the differences between dug wells and drilled wells will help you make informed choices. This article breaks down construction methods, costs, water quality, maintenance, lifespan, inspection checklists, and what you should know as a new homeowner.

The basic definitions

You should first know what each term means in simple language. Each type of well has distinct construction techniques and performance characteristics that affect how reliable and safe your water supply will be.

What is a dug well?

A dug well is an older type of well that’s typically excavated by hand, backhoe, or an excavator. They are usually shallow—often less than 50 feet deep—and wide, lined with stone, brick, tile, or concrete rings to keep the sides from collapsing.

What is a drilled well?

A drilled well is created using rotary or cable-tool drilling equipment, producing a narrow borehole that can reach hundreds to thousands of feet deep. These wells are cased with steel or PVC to protect the bore and are often completed with screened sections to let groundwater enter while keeping out sediment.

How they are constructed

Understanding construction methods helps you evaluate durability, contamination risks, and what repairs might look like down the road.

Construction of a dug well

Dug wells are often dug with earth-moving equipment or by hand. Builders line them with materials like brick or concrete to prevent collapse and add a simple cover. They rely on shallow groundwater in unconsolidated materials like sand or gravel.

Construction of a drilled well

Drilled wells are made with powerful drilling rigs that create a narrow, deep hole through bedrock and multiple soil layers. The well is installed with a steel or PVC casing and often a screened interval at the water-bearing zone. A well cap and surface seal are installed to keep contaminants out.

Typical depths and sizes

Depth and diameter are major factors that affect yield, susceptibility to drought, and contamination.

• Dug wells: Shallow, commonly 10–50 feet deep, with diameters up to several feet.
• Drilled wells: Much deeper, often 100–1,000+ feet deep, with diameters typically 4–8 inches for residential use.

Why depth matters

Depth affects both water quantity and water quality. Deeper wells often tap confined or artesian aquifers that are more protected from surface contamination. Shallow wells rely on near-surface aquifers, which are more vulnerable to pollutants and seasonal changes.

Water yield and reliability

You want a steady water supply for daily needs. Yield and recovery rates determine how well a well can meet household demands.

Dug well yields

Dug wells usually have lower yields and slower recovery because they draw from limited, shallow aquifers. They might run dry during droughts or high-demand periods. Yields vary greatly depending on local geology and the size of the aquifer.

Drilled well yields

Drilled wells generally offer higher and more reliable yields, especially when they tap confined aquifers or deeper water-bearing formations. They can often sustain higher pump rates and are less affected by short-term droughts.

Water quality differences

Water quality is a major concern when buying a home with a well. Different well types face different contamination risks.

Contamination risks for dug wells

Because dug wells are shallow and have wide openings, they are more susceptible to bacteria, viruses, fertilizers, pesticides, surface runoff, septic system failure, and animal waste. Infiltration around the well head is a common issue if not properly sealed and capped.

Contamination risks for drilled wells

Drilled wells are less likely to be contaminated by surface pollutants due to depth and the use of proper casing and seals. However, they can still be affected by naturally occurring contaminants (like arsenic, radon, iron, manganese, or nitrates) depending on local geology. Poorly constructed or old drilled wells without proper seals can still have contamination issues.

Lifespan and durability

You’ll want to know how long a well can last and what maintenance may be expected.

Dug well lifespan

Dug wells tend to have shorter service lives due to collapse, degradation of lining materials, and contamination. Without proper maintenance and upgrades, many dug wells require significant repair or abandonment within decades, especially in shifting soils or flood-prone areas.

Drilled well lifespan

Drilled wells can last many decades—often 50 years or more—when properly constructed and maintained. Corrosion of steel casing, well screen fouling, or pump failure are common issues, but mechanical and rehabilitation solutions extend life considerably.

Cost differences

Costs are a significant factor when considering a property with a well, whether you need a new well or repairs.

Initial construction cost

• Dug wells: Lower initial cost to dig, but costs vary with excavation difficulty and lining materials.
• Drilled wells: Higher initial cost because of equipment, depth, and materials, but they often provide better long-term value.

Repair and rehabilitation costs

Dug well repairs can be less expensive in some cases (simple lining or cover upgrades), but major rehabilitation or conversion to a drilled well is costly. Drilled wells may require pump replacement, well rehabilitation (acidizing, air lifting, or jetting), or redeveloping the well, which can also be expensive but usually addresses yield and quality effectively.

Regulatory and permitting considerations

Regulations vary widely by state, county, and municipality, and they can affect your responsibilities as a homeowner.

Permitting for dug wells

Some jurisdictions limit new dug wells or regulate their construction due to contamination risks. Existing dug wells might require upgrades or permits when transferring property or modifying the system.

Permitting for drilled wells

Drilled wells generally require formal permits, well logs, and inspections, especially when deeper than a certain threshold. Well drillers often register the well and provide construction details to local authorities.

Inspection and documentation for home purchase

When buying a house with a well, thorough inspections and documentation are critical to avoid surprises.

What to ask for in documentation

Request well construction records, pump specifications, recent water tests, maintenance records, and any permits or reports from local water authorities. Well logs can reveal depth, casing type, screened intervals, and water-bearing formations.

Professional inspections you should get

Hire a licensed well inspector or hydrogeologist to evaluate the well’s physical condition, pump operation, and water quality. Ask for a flow test, static and pumping water levels, pressure tank assessment, and a full water-quality analysis.

Water testing: what to test for and when

Regular testing protects your family’s health and helps identify system issues early.

Basic water tests you should get

Test for total coliform bacteria, E. coli, nitrates/nitrites, and pH as a baseline. These indicate microbiological contamination, fertilizer or septic impact, and corrosivity, respectively.

Expanded water tests

Consider testing for arsenic, lead, radon, iron, manganese, sulfate, chloride, total dissolved solids (TDS), hardness, and volatile organic compounds (VOCs) depending on regional risks and land use. Seasonal testing is important after flooding or land disturbance.

Recommended testing frequency

• Bacteria (total coliform/E. coli): at least annually and after any well servicing or contamination event.
• Nitrates: annually, especially for shallow wells or if you have young children, pregnant women, or livestock.
• Full panel: every 2–3 years or if you notice changes in taste, odor, or appearance.

Maintenance responsibilities for homeowners

Owning a well means you’re responsible for its upkeep. Knowing the routine tasks avoids surprises.

Routine maintenance tasks

Check well cap and casing integrity annually, test water quality, maintain a disinfected area around the well, and schedule pump and pressure tank inspections every few years. Keep hazardous materials and trees away from the well.

What you can do yourself

You can perform visual checks, keep the area clean, and coordinate water sampling. For anything involving the pump, wiring, or well interior, hire a licensed professional.

Signs of well problems you should watch for

Early warning signs help you get professional help before issues escalate.

• Unusual taste, odor, or discoloration in water.
• Decreased water pressure or flow.
• Intermittent water supply or sudden drop to dry.
• High sediment in water or gritty residue.
• Corrosion on fixtures, staining, or pipe clogs.
• Sputtering faucets or air in the lines.

If you notice any of these, test the water and contact a well professional.

Well pumps and pressure systems

Understanding components helps you diagnose issues and estimate repair costs.

Types of pumps

• Jet pumps: Common for shallow wells; mounted above ground.
• Submersible pumps: Installed in the well for deeper systems; more efficient and quieter.
• Hand pumps: Manual systems for emergency or rural properties.

Pressure tanks and controls

Pressure tanks store a small volume of water to smooth pump cycling and maintain consistent pressure. Expansion tanks or pressure switches may need adjustment, repair, or replacement over time.

Treatment options and filtration

If tests reveal contaminants, you’ll need treatment tailored to the problem. Treatment selection depends on the contaminant and water chemistry.

Common treatment approaches

• Disinfection (chlorination or UV) for bacteria.
• Reverse osmosis for nitrates and many inorganic contaminants.
• Ion exchange (water softeners) for hardness.
• Activated carbon filters for organic compounds and taste/odor.
• Aeration and filtration for iron and manganese removal.

Point-of-entry vs point-of-use systems

Point-of-entry (whole-house) systems treat all water entering your home. Point-of-use systems (under-sink filters) treat water at a specific tap, usually for drinking and cooking. Choose based on contaminant type, household needs, and budget.

Abandonment and replacement

Wells that are no longer functional or safe must be properly abandoned to avoid hazards.

Proper well abandonment

A properly abandoned well is filled or sealed according to local codes, usually with bentonite clay or grout, to prevent groundwater contamination and physical hazards. Do not attempt abandonment without a licensed contractor.

When to replace a well

Consider replacement if the well’s yield is consistently inadequate, contamination persists despite treatment, or the cost of repeated repairs exceeds the cost of drilling a new, deeper well.

Insurance, liability, and financing considerations

Owning a well affects your insurance needs and potentially the transaction process when buying a home.

Homeowners insurance

Standard policies may not cover well systems or water contamination. Check with your insurer about coverage for well components, pump failure, and liability for injuries near the well.

Mortgage and financing

Lenders may require proof of a reliable water source and recent water tests for mortgage approval. Some financing options or home inspections will specifically address wells.

Buying a house with a well: key questions to ask

When you’re buying, ask targeted questions to reveal potential issues and future costs.

• How old is the well and the pump?
• Can you provide the well log, construction details, and permits?
• When was the last water test, and can you see results?
• Have there been recurring problems (contamination, low yield, mechanical failures)?
• What is the measured yield and static water level?
• Has the well ever been disinfected or rehabilitated?

What information to obtain before closing

Ask for recent pump inspection reports, maintenance receipts, water-quality tests, and any warranties on equipment. Verify that the well meets current local code requirements for safety and construction.

Negotiation tips for buyers

Knowing typical costs and risks gives you leverage in negotiations.

• Ask the seller to provide a recent comprehensive water test as a condition of sale.
• Request credits or price reduction if the well needs pump replacement or rehabilitation.
• Require that any known problems be remedied before closing or establish an escrow for repairs.

Cost estimates and budgeting

While costs vary by region, it helps to have ballpark figures for common expenses.

These are general estimates; costs depend on depth, access, local labor rates, and regional factors.

Regional considerations and geology

Local geology determines which well type is appropriate and what contaminants you might expect.

Areas where dug wells are common

Dug wells are more common in areas with shallow, productive water tables or older rural properties where simple excavation was practical. In floodplains or flat terrain with high groundwater, dug wells were historically used.

Areas favoring drilled wells

Where bedrock, deep aquifers, or variable groundwater levels exist, drilled wells are preferred. Regions with known contaminants in shallow layers may require deeper drilled wells to reach safer water.

Environmental and health considerations

You should prioritize safe water for your family and understand environmental impacts.

Public health risks

Unsafe well water can carry pathogens that cause gastrointestinal illness or chronic exposure to contaminants like arsenic can increase cancer risk. Regular testing and prompt treatment are essential.

Environmental impacts

Improperly abandoned wells can act as conduits for pollutants, compromising aquifers. Responsible construction, sealing, and maintenance protect groundwater resources.

Common myths and misconceptions

Addressing myths will help you separate fact from fiction when evaluating properties.

Myth: Deeper wells always have better water

Depth helps reduce surface contamination risk but doesn’t guarantee safety. Deep wells can have naturally occurring contaminants like arsenic or radon, so testing is still necessary.

Myth: If a well worked before, it will always work

Wells can change over time due to seasonal fluctuations, drought, land use changes, or pump aging. Recent testing and inspection are crucial.

When to call a professional

Knowing when to call a licensed well contractor or hydrogeologist saves time and prevents hazards.

• Persistent or unexplained water quality problems.
• Sudden drops in yield or pressure.
• Visible structural damage to the well or casing.
• Electrical issues with the pump or persistent cycling.
• When abandoning or drilling a new well.

Final checklist for buyers

Use this checklist to evaluate a well before you buy a home.

• Obtain well log, permits, and maintenance records.
• Ask the seller for recent water tests; request updated testing if none exists.
• Hire a licensed well inspector to test yield, pressure, and pump performance.
• Verify construction details (depth, casing, screened interval).
• Confirm local regulations and whether the well meets current codes.
• Budget for immediate and future maintenance or treatment.
• Check insurance coverage for well-related issues.

Conclusion

You’ll find that the main differences between dug wells and drilled wells involve depth, construction method, contamination risk, reliability, and long-term cost. Dug wells are shallow, more vulnerable to contamination, and often cheaper initially but riskier in the long run. Drilled wells are deeper, more durable, and generally provide more reliable water but come with higher upfront costs. As a prospective homeowner, ask for documentation, insist on professional testing and inspection, and budget for ongoing maintenance and potential treatment. Making these steps part of your due diligence will help protect your health, finances, and peace of mind.