Complete Guide to Submersible Well Pumps

Submersible well pumps are widely used to extract groundwater from deep wells and boreholes.

They are commonly used for:

① Agricultural irrigation

② Industrial water supply

③ Municipal water systems

④ Mining and construction projects

⑤ Residential and community water supply

⑥ Livestock and remote water supply

Unlike a surface pump, a submersible well pump operates below the water level.

The pump pushes water upward through the rising pipe instead of pulling water through a long suction line.

This design makes submersible well pumps especially suitable for:

① Deep wells

② Boreholes

③ High-head water supply systems

④ Continuous groundwater extraction

However, choosing the correct pump is not simply a matter of selecting a larger motor or a bigger pump diameter.

A correct pump selection should consider:

① Required flow rate

② Total dynamic head

③ Static water level

④ Dynamic water level

⑤ Well casing diameter

⑥ Pump installation depth

⑦ Water quality

⑧ Sand content

⑨ Pump material

⑩ Power supply

⑪ Required discharge pressure

⑫ Expected operating hours

In this guide, we explain:

① What a submersible well pump is

② How a submersible well pump works

③ How to calculate flow and head

④ How to choose pump size and motor power

⑤ How to select pump materials

⑥ How to install a deep-well pump

⑦ How to commission and maintain the pump

⑧ How to identify common pump problems

Submersible Well Pump Selection at a Glance

A submersible well pump should be selected from the required flow and Total Dynamic Head, not from well depth, pump diameter or motor horsepower alone.

The correct selection process is:

①Calculate the required flow from the actual water demand and available pumping hours.

②Calculate Total Dynamic Head from the dynamic water level, discharge elevation, required pressure and pipeline losses.

③Confirm the well casing diameter, installation depth and sustainable well yield.

④Review water quality, sand content, temperature and corrosion risk.

⑤Confirm voltage, frequency, phase and starting method.

⑥Plot the required duty point on the pump performance curve.

⑦Select the pump model, number of stages, motor power, materials and protection system.

Contents

1. What Is a Submersible Well Pump?
2. How Does a Submersible Well Pump Work?
3. What Are the Main Components?
4. Where Are Submersible Well Pumps Used?
5. How to Choose a Submersible Well Pump
6. How to Install a Submersible Well Pump
7. How to Start a Newly Installed Pump
8. How to Maintain a Submersible Well Pump
9. Common Submersible Well Pump Problems
10. How Long Does a Submersible Well Pump Last?
11. When Should You Repair or Replace a Well Pump?
12. Information Required for Pump Selection
13. Frequently Asked Questions
14. Explore SLAPK Submersible Well Pumps

1. What Is a Submersible Well Pump?

A submersible well pump is a pump-and-motor assembly designed to operate fully submerged in water.

The pump is normally installed inside:

① A deep well

② A borehole

③ A groundwater source

④ Another suitable deep-water installation

The basic pumping process is:

① Water enters through the pump inlet.

② The impeller increases the velocity of the water.

③ The diffuser converts part of the velocity into pressure.

④ Water passes through the next hydraulic stage.

⑤ Pressure increases stage by stage.

⑥ High-pressure water leaves the pump through the rising pipe.

Most deep-well submersible pumps use a multistage centrifugal design.

In simple terms:

The pump uses multiple impellers and diffusers to gradually increase water pressure.

The number and hydraulic design of the stages affect:

① Pump flow

② Pump head

③ Pump efficiency

④ Motor power requirement

⑤ Suitable operating range

A complete deep-well pumping installation normally includes:

① Submersible well pump

② Submersible motor

③ Rising pipe

④ Submersible power cable

⑤ Check valve

⑥ Control panel

⑦ Water-level protection

⑧ Pressure or flow monitoring equipment

For a more detailed introduction, read What Is a Submersible Well Pump?

2. How Does a Submersible Well Pump Work?

A submersible well pump converts electrical energy into hydraulic energy.

The operating process can be divided into five main steps.

(1)  The Submersible Motor Starts

Electrical power is supplied to the submersible motor.

The motor begins to rotate.

Depending on the project, the motor may use:

① Different voltages

② 50 Hz or 60 Hz frequency

③ Single-phase or three-phase power

④ Direct-on-line starting

⑤ Star-delta starting

⑥ Soft starting

⑦ Variable-frequency control

The correct electrical configuration should be confirmed before the pump is manufactured or installed.

(2)  The Motor Rotates the Pump Shaft

The motor transfers torque to the pump shaft.

The shaft drives the hydraulic components inside the pump.

These components mainly include:

① Impellers

② Diffusers

③ Bearings

④ Bushings

The rotating components must remain stable and correctly aligned during operation.

(3)  Water Enters the First Impeller

Water enters through the inlet screen.

The first impeller rotates and transfers energy to the water.

As a result, the water velocity increases.

(4)  Pressure Increases Stage by Stage

Water leaving the impeller enters a diffuser.

The diffuser performs two important functions:

① It converts part of the water velocity into pressure.

② It guides the water into the next impeller.

The process is repeated:

Impeller → Diffuser → Impeller → Diffuser

Each hydraulic stage adds energy to the water.

This is why multistage pumps can generate high discharge pressure.

(5)  Water Is Pushed Toward the Surface

The pump must generate enough pressure to overcome the total system resistance.

This normally includes:

① Vertical lifting height

② Rising-pipe friction loss

③ Surface-pipeline friction loss

④ Valve and fitting losses

⑤ Required outlet pressure

⑥ Additional elevation after the wellhead

Because the pump operates below the water level, it does not normally require priming like many surface-mounted pumps.

Read our detailed guide about the structure and working principle of a submersible well pump.

3. What Are the Main Components of a Submersible Well Pump?

Understanding the main pump components can make selection, maintenance, and troubleshooting easier.

(1)  Submersible Motor

The motor provides the mechanical power required to operate the pump.

Submersible motors are designed to work underwater.

Depending on the design, they may be:

① Water-filled motors

② Oil-filled motors

③ Other sealed submersible motor designs

Important motor parameters include:

① Motor power

② Voltage

③ Frequency

④ Number of phases

⑤ Starting method

⑥ Rated current

⑦ Motor protection requirements

The motor must also receive adequate cooling during operation.

Motor cooling can be affected by:

① Pump installation depth

② Water velocity around the motor

③ Well casing diameter

④ Dynamic water level

⑤ Motor position

⑥ Use of a cooling sleeve

Important:

Insufficient motor cooling can increase motor temperature and shorten motor service life.

(2)  Impellers

Impellers transfer rotational energy to the water.

A multistage well pump contains several impellers.

The impeller design affects:

① Pump flow

② Pump head

③ Pump efficiency

④ Hydraulic stability

⑤ Sand resistance

Impeller material should also match the actual water conditions.

Common considerations include:

① Corrosion

② Sand content

③ Particle wear

④ Water chemistry

⑤ Required service life

(3)  Diffusers

Diffusers are installed between hydraulic stages.

Their main functions are:

① Collect water leaving the impeller.

② Convert part of the water velocity into pressure.

③ Guide water into the next pump stage.

Wear or blockage inside the diffuser passages may cause:

① Lower pump flow

② Lower pump head

③ Reduced efficiency

④ Unstable hydraulic performance

(4)  Pump Shaft

The pump shaft transfers torque from the motor to the impellers.

Shaft condition directly affects the rotating assembly.

Common shaft-related problems include:

① Shaft wear

② Shaft bending

③ Poor alignment

④ Excessive vibration

⑤ Abrasive damage

⑥ Unbalanced hydraulic forces

A damaged shaft may also accelerate wear of:

① Bearings

② Bushings

③ Impellers

④ Other rotating components

(5)  Bearings and Bushings

Bearings and bushings support the rotating assembly.

Their condition affects:

① Shaft stability

② Pump vibration

③ Mechanical wear

④ Pump service life

Water containing abrasive particles may accelerate bearing and bushing wear.

This is especially important in wells with high sand content.

(6) Inlet Screen

The inlet screen helps prevent larger debris from entering the pump.

However:

A standard inlet screen cannot completely remove fine sand.

It also cannot protect a conventional clean-water pump from highly abrasive particles.

For wells containing significant sediment, read our High Sand Content Deep Well Pump Selection Guide.

(7)  Check Valve

A check valve helps prevent water in the rising pipe from flowing backward after the pump stops.

A suitable check valve can help reduce reverse flow.

Incorrect check-valve selection or installation may cause:

① Reverse water flow

② Water hammer

③ Pressure fluctuations

④ Repeated pump cycling

⑤ Additional mechanical stress

⑥ Damage to the rising-pipe system

4. Where Are Submersible Well Pumps Used?

Submersible well pumps are used wherever water must be extracted from a deep water source.

Typical applications include the following.

(1)  Agricultural Irrigation

Submersible well pumps can supply water to:

① Sprinkler irrigation systems

② Drip irrigation systems

③ Farm storage tanks

④ Agricultural distribution networks

⑤ Livestock water systems

The main selection factors include:

① Required irrigation flow

② Dynamic water level

③ Field elevation

④ Pipeline length

⑤ Pipe diameter

⑥ Required irrigation pressure

An irrigation pump should not be selected according to well depth alone.

(2)  Municipal Water Supply

Municipal projects may use deep-well pumps to transfer groundwater to:

① Water treatment plants

② Storage reservoirs

③ Municipal pipe networks

④ Community water systems

⑤ Booster or distribution systems

These projects often require:

① Continuous operation

② Stable pump performance

③ Reliable motor protection

④ Suitable material selection

⑤ Performance monitoring

(3)  Industrial Water Supply

Factories may use deep-well pumps for:

① Process water

② Cooling water

③ Cleaning systems

④ Raw water transfer

⑤ General utility water

Before selecting the pump, check:

① Water chemistry

② Required flow

③ Required pressure

④ Daily operating hours

⑤ Electrical supply

(4)  Mining and Construction

Typical applications include:

① Groundwater removal

② Mine water transfer

③ Shaft drainage

④ Construction water supply

⑤ High-head water transfer

Water in mining and construction environments may contain:

① Sand

② Minerals

③ Sediment

④ Corrosive substances

⑤ Other abrasive materials

A standard clean-water pump may not always be suitable.

(5)  Seawater and Corrosive Water

Special material configurations may be required for corrosive water conditions.

Possible materials include:

① SS316

② SS316L

③ Duplex stainless steel

④ Super duplex stainless steel

⑤ SS904L

⑥ Bronze

⑦ Other special alloys

Important:

Do not select a material based only on the general description “corrosive water.”

The actual liquid composition should be checked.

(6)  Remote Water-Supply Projects

Deep-well pumps can also be used for:

① Remote communities

② Livestock watering

③ Mountain areas

④ Plateau regions

⑤ Remote industrial sites

⑥ Community water projects

Before pump selection, always confirm:

① Available voltage

② Frequency

③ Grid stability

④ Generator capacity, if applicable

⑤ Required control method

5. How to Choose a Submersible Well Pump

A submersible well pump should be selected according to the actual operating point.

The two most important parameters are:

① Required flow rate

② Required total dynamic head

Motor power alone is not enough to select a pump.

The following 10-step process can be used for most projects.

Step 1: Determine the Required Flow Rate

Flow rate describes how much water the pump must deliver within a specific period.

Common flow units include:

① m³/h

② L/s

③ L/min

④ GPM

The required flow depends on the application.

For Agricultural Irrigation

Consider:

① Field area

② Crop water demand

③ Irrigation duration

④ Number of sprinklers

⑤ Sprinkler flow requirement

⑥ Irrigation zones

For Industrial Water Systems

Consider:

① Production water demand

② Peak consumption

③ Storage tank capacity

④ Daily operating hours

⑤ Future system expansion

For Municipal Water Supply

Consider:

① Population or user demand

② Peak water consumption

③ Reservoir capacity

④ Pump operating schedule

⑤ Required redundancy

Important:

Do not select a pump according to the maximum possible flow without considering the well’s sustainable yield.

If:

Pump flow > Well recovery rate

the dynamic water level may continue to fall.

This may cause:

① Unstable water supply

② Pump dry running

③ Insufficient motor cooling

④ Pump performance reduction

⑤ Premature pump failure

Read How to Calculate the Required Well Pump Flow Rate

Step 2: Calculate Total Dynamic Head

Total dynamic head, or TDH, is the total pressure the pump must generate at the required flow.

It normally includes:

① Vertical lifting height

② Rising-pipe friction loss

③ Surface-pipeline friction loss

④ Valve and fitting losses

⑤ Required discharge pressure

⑥ Additional elevation after the wellhead

Common Mistake

Total well depth is not automatically equal to pump head.

For example:

① Total well depth: 300 m

② Dynamic water level: 120 m below ground

③ Discharge point: 20 m above ground

④ Additional pressure is required at the outlet

The pump should not automatically be selected for 300 m head.

The actual total dynamic head must be calculated.

Simple principle:

Pump head should be calculated from the actual operating water level and complete system resistance.

Read How to Calculate Total Dynamic Head for a Submersible Well Pump

Step 3: Confirm Static and Dynamic Water Levels

Two water levels are especially important.

(1)  Static Water Level

The static water level is the water level when the pump is not operating.

(2)  Dynamic Water Level

The dynamic water level is the water level while the pump is running.

For pump selection:

The dynamic water level is normally more important.

It represents the actual operating condition.

Before selecting the pump, collect:

① Total well depth

② Static water level

③ Dynamic water level

④ Seasonal water-level variation

⑤ Well recovery rate

⑥ Planned pump installation depth

The pump inlet should remain adequately submerged during operation.

However, the pump should not normally be installed unnecessarily close to the bottom of the well.

Installing the pump too close to the bottom may increase the risk of:

① Sand intake

② Sediment intake

③ Pump wear

④ Hydraulic blockage

Read How to Select a Pump Based on Well Depth

Step 4: Check the Well Casing Diameter

The pump outside diameter must be smaller than the internal diameter of the well casing.

Sufficient clearance is required for:

① Safe pump installation

② Pump removal during maintenance

③ Water circulation around the motor

④ Motor cooling

⑤ Power cable protection

⑥ Prevention of pump contact with the casing

Common industrial deep-well pump diameters may include:

① 8 inch

② 10 inch

③ 12 inch

④ 14 inch

⑤ 16 inch

⑥ 18 inch

The actual pump diameter depends on the project.

Important:

A larger pump diameter does not automatically mean better pump performance.

You should consider:

① Required flow

② Required head

③ Well diameter

④ Motor size

⑤ Motor cooling

⑥ Installation conditions

Step 5: Select the Required Motor Power

Motor power should be selected according to:

① Required flow

② Required head

③ Pump efficiency

④ Actual operating point

⑤ Hydraulic power requirement

⑥ Suitable safety margin

Do not select the motor independently from the pump curve.

If the Motor Is Too Small

Possible problems include:

① Motor overload

② High motor current

③ Motor overheating

④ Frequent tripping

⑤ Shortened motor life

If the Motor Is Unnecessarily Large

Possible disadvantages include:

① Higher purchase cost

② Larger electrical equipment

③ Higher cable cost

④ Higher control-panel cost

⑤ Possible system inefficiency

Also confirm:

① Voltage

② Frequency

③ Single-phase or three-phase power

④ Starting method

⑤ Cable length

⑥ Control panel

⑦ Generator capacity

⑧ Transformer capacity

Read How Many HP Does a Well Pump Need?

Step 6: Evaluate the Water Quality

Water quality directly affects:

① Pump material

② Hydraulic wear

③ Corrosion resistance

④ Pump service life

Before selecting a pump, check:

① Sand content

② Silt content

③ Chloride concentration

④ Salinity

⑤ pH value

⑥ Dissolved minerals

⑦ Corrosive chemicals

⑧ Water temperature

⑨ Suspended solids

Where possible, provide a water-analysis report to the pump manufacturer.

Important:

The description “clean water” is often not enough for accurate pump selection.

For example, apparently clear water may still contain:

① High chlorides

② Dissolved salts

③ Fine abrasive particles

④ Corrosive minerals

Step 7: Choose the Pump Material

Pump material should match the actual water conditions.

(1)  Cast Iron

Cast iron may be suitable for:

① General freshwater

② Standard groundwater

③ Water with controlled chemistry

④ Cost-sensitive projects

Its main advantage is usually cost-effectiveness.

(2)  SS304 Stainless Steel

SS304 may be considered for:

① General corrosion resistance

② Suitable freshwater applications

③ Projects requiring a stainless steel structure

However, it may not be suitable for every chloride-rich environment.

(3)  SS316 or SS316L

SS316 and SS316L may provide better corrosion resistance for certain demanding water conditions.

The suitability depends on:

① Chloride concentration

② Water temperature

③ pH

④ Other chemical conditions

(4) Duplex and Super Duplex Stainless Steel

Duplex and super duplex stainless steels may be considered for more demanding corrosion conditions.

Applications should be evaluated according to actual water chemistry.

(5)SS904L, Bronze, or Special Materials

Special projects may require:

① SS904L

② Bronze

③ Other corrosion-resistant alloys

The final choice should consider:

① Chloride concentration

② pH

③ Salinity

④ Water temperature

⑤ Required service life

⑥ Project standards

⑦ Project budget

Read our Deep Well Water Pump Material Selection Guide.

For corrosive applications, explore our Stainless Steel Submersible Pump Range.

Step 8: Check the Sand Content

Sand is one of the most common problems in deep wells.

Abrasive particles may damage:

① Impellers

② Diffusers

③ Bushings

④ Bearings

⑤ Pump shafts

⑥ Hydraulic surfaces

⑦ Other rotating components

For a high-sand well, do not select a pump based only on flow and head.

You should also check:

① Sand concentration

② Particle size

③ Particle hardness

④ Pump speed

⑤ Hydraulic passage design

⑥ Wear-resistant material

⑦ Expected operating hours

Important

Repeated pump wear may not always be caused by poor pump quality.

The real problem may be:

① A damaged well screen

② Well casing problems

③ Incorrect pump installation depth

④ Excessive pumping rate

⑤ Geological conditions

⑥ Continuous sand entry

Before replacing a repeatedly worn pump, inspect the complete well system.

Read our High Sand Content Deep Well Pump Selection Guide.

Step 9: Review the Pump Curve

Before selecting a pump model, check the pump performance curve.

A pump curve normally shows the relationship between:

① Flow

② Head

③ Efficiency

④ Motor power

⑤ Sometimes other hydraulic data

The required operating point should fall within the recommended pump operating range.

Avoid Operating at an Extreme Point

Continuous operation too far from the preferred range may cause:

① Reduced efficiency

② Higher vibration

③ Hydraulic instability

④ Increased bearing load

⑤ Motor overload

⑥ Faster component wear

⑦ Higher energy consumption

Important:

Do not select a pump simply because its maximum head is higher than the required head.

You must check flow and head at the same operating point.

Read How to Size a Submersible Well Pump

Step 10: Confirm the Motor Protection and Control System

A suitable pump control system should protect the motor against common electrical and operating problems.

Depending on the project, protection may include:

① Overload protection

② Short-circuit protection

③ Phase-loss protection

④ Phase-imbalance protection

⑤ Under-voltage protection

⑥ Over-voltage protection

⑦ Dry-run protection

⑧ High-temperature protection

⑨ Frequent-start protection

⑩ Low-water-level protection

Why Is Motor Protection Important?

Without suitable protection:

① A blocked pump may overload the motor.

② Phase loss may damage a three-phase motor.

③ Low voltage may increase current.

④ Dry running may cause pump damage.

⑤ Frequent starts may increase motor temperature.

Select the Correct Starting Method

The starting method depends on:

① Motor power

② Power-grid capacity

③ Project requirements

④ Voltage

⑤ Required automation

Possible starting methods include:

① Direct-on-line starting

② Star-delta starting

③ Soft starter

④ Variable frequency drive

The control panel should be selected according to the actual motor and site conditions.

6. How to Install a Submersible Well Pump

Correct installation is essential for safe and reliable pump operation.

Before installation, confirm:

① Pump model and performance

② Motor voltage and frequency

③ Well casing diameter

④ Total well depth

⑤ Static water level

⑥ Dynamic water level

⑦ Pump installation depth

⑧ Rising-pipe specification

⑨ Cable length and cable size

⑩ Check-valve arrangement

⑪ Control-panel settings

⑫ Direction of rotation, where applicable

The installation process should include the following checks.

(1).  Confirm the Pump Installation Depth

The pump should normally be installed below the lowest expected dynamic water level.

This helps ensure:

① Adequate pump submergence

② Stable water intake

③ Suitable motor cooling

However, the pump should not normally be installed too close to the bottom of the well.

A pump installed too close to sediment may experience:

① Higher sand intake

② Sediment blockage

③ Faster hydraulic wear

④ Bearing and bushing damage

The correct installation depth depends on:

① Well design

② Dynamic water level

③ Seasonal water variation

④ Sand conditions

⑤ Pump configuration

(2).  Select the Correct Rising Pipe

The rising pipe carries water from the pump to the surface.

The pipe must withstand:

① Pump discharge pressure

② Weight of the pump

③ Weight of the water column

④ Starting and stopping forces

⑤ Water hammer

⑥ Corrosion conditions

Pipe diameter is also important.

If the Pipe Is Too Small

Possible problems include:

① High friction loss

② Higher required pump head

③ Increased energy consumption

④ Lower system flow

If the Pipe Is Too Large

Possible disadvantages may include:

① Higher pipe cost

② More difficult installation

③ Larger fittings and valves

The rising-pipe diameter should be selected according to:

① Required flow

② Water velocity

③ Pipe length

④ Allowable friction loss

⑤ Installation requirements

(3).  Select the Correct Power Cable

The power cable should be selected according to:

① Motor rated current

② Voltage

③ Cable length

④ Starting current

⑤ Allowable voltage drop

⑥ Installation environment

The cable must be suitable for submersible operation.

Cable joints should be:

① Waterproof

② Mechanically secure

③ Electrically insulated

④ Suitable for long-term underwater use

Important:

An undersized cable may cause excessive voltage drop.

This can result in:

① Higher motor current

② Motor overheating

③ Starting problems

④ Reduced motor life

(4).  Check the Check-Valve Arrangement

The check valve helps prevent reverse water flow after the pump stops.

Before installation, confirm:

① Valve size

② Pressure rating

③ Installation direction

④ Valve position

⑤ Number of check valves, where applicable

Incorrect check-valve arrangements may contribute to:

① Water hammer

② Reverse rotation

③ Pressure fluctuations

④ Mechanical stress

(5).  Protect the Power Cable During Installation

The cable should be secured to the rising pipe at suitable intervals.

During pump lowering:

① Do not pull the pump by the power cable.

② Do not allow the cable to rub against sharp surfaces.

③ Avoid excessive cable tension.

④ Protect cable joints.

⑤ Prevent the cable from becoming trapped between the pump and well casing.

Cable damage may cause:

① Electrical leakage

② Short circuit

③ Motor protection trips

④ Motor failure

(6).  Check Pump Rotation

For applicable three-phase pump systems, incorrect rotation may reduce pump performance.

Possible signs include:

① Low flow

② Low head

③ Abnormal motor current

Before continuous operation, follow the correct commissioning procedure to verify pump performance.

Do not repeatedly reverse phases without following the motor and pump instructions.

(7).  Confirm the Control Panel Settings

Before starting the pump, check:

① Motor rated current

② Overload setting

③ Voltage protection

④ Phase protection

⑤ Dry-run protection

⑥ Water-level control

⑦ Starting method

⑧ Stopping conditions

Incorrect control-panel settings may cause either:

① Insufficient protection

or

② Unnecessary pump trips

A complete article will be published as Submersible Well Pump Installation Guide

7. How to Start a Newly Installed Submersible Well Pump

After installation, the pump should be started under controlled conditions.

Do not simply start the pump and leave the site.

The initial operating data should be recorded.

(1)  Check the Electrical Data

Record:

① Voltage

② Motor current

③ Phase balance

④ Starting condition

⑤ Control-panel status

Compare the measured values with the motor specifications.

(2)  Check the Hydraulic Data

Record:

① Actual flow rate

② Discharge pressure

③ Dynamic water level

④ Outlet conditions

The actual operating point should be compared with the selected pump curve.

(3) Check the Mechanical Condition

Observe:

① Abnormal noise

② Excessive vibration

③ Unstable flow

④ Pressure fluctuations

⑤ Abnormal pipe movement

(4) Check the Control System

Confirm:

① Pump start signal

② Pump stop signal

③ Protection settings

④ Alarm status

⑤ Water-level control

⑥ Pressure or flow control

If the Actual Flow Is Too High

Possible risks include:

① The dynamic water level may fall quickly.

② The well may not recover fast enough.

③ The pump may operate outside its preferred range.

④ Motor load may change.

⑤ Sand intake may increase.

If Flow or Pressure Is Too Low

Check:

① Pump rotation

② Dynamic water level

③ Valve position

④ Pipeline resistance

⑤ Voltage

⑥ Rising-pipe leakage

⑦ Pump hydraulic condition

⑧ Pump selection

Important:

Keep the initial commissioning data.

It can be used as a reference during future maintenance and troubleshooting.

8. How to Maintain a Submersible Well Pump

Because the pump operates underwater, routine maintenance often depends on performance monitoring.

Regularly record:

① Flow rate

② Discharge pressure

③ Motor current

④ Voltage

⑤ Dynamic water level

⑥ Running hours

⑦ Number of starts

⑧ Vibration

⑨ Abnormal noise

⑩ Insulation condition, where applicable

Changes in operating data can provide an early warning.

(1)  Falling Flow Rate

Possible causes include:

① Falling water level

② Blocked pump inlet

③ Hydraulic wear

④ Sand damage

⑤ Pipeline blockage

⑥ Low voltage

(2)  Increasing Motor Current

Possible causes include:

① Motor overload

② Mechanical friction

③ Sand accumulation

④ Pump blockage

⑤ Bearing problems

⑥ Motor problems

(3)  Increasing Vibration

Possible causes include:

① Component wear

② Impeller imbalance

③ Shaft problems

④ Bearing or bushing wear

⑤ Hydraulic instability

(4)  Frequent Pump Starting

Possible causes include:

① Incorrect control settings

② Pipeline leakage

③ Pressure-system problems

④ Insufficient storage capacity

⑤ Incorrect sensor settings

The most important maintenance principle is:

Compare current operating data with the original commissioning data.

Read our Submersible Well Pump Maintenance Guide.

9. What Are the Most Common Submersible Well Pump Problems?

The following problems are common in deep-well pumping systems.

(1)  The Pump Runs but Delivers No Water

Possible causes include:

① Water level below the pump inlet

② Incorrect rotation

③ Blocked inlet

④ Damaged impellers

⑤ Broken shaft or coupling

⑥ Closed discharge valve

⑦ Leaking rising pipe

⑧ Failed check valve

Read Why Is My Submersible Well Pump Not Pumping Water?

(2)  The Pump Is Losing Flow

Possible causes include:

① Falling dynamic water level

② Clogged inlet screen

③ Worn impellers

④ Worn diffusers

⑤ Sand damage

⑥ Low voltage

⑦ Pipeline blockage

⑧ Valve problems

⑨ Changing system resistance

Read Is Your Submersible Well Pump Losing Flow? Three Common Causes and Fixes.

(3)  The Pump Keeps Running

Possible causes include:

① Pump capacity is too small.

② The dynamic water level is falling.

③ The pipeline is leaking.

④ Pressure settings are incorrect.

⑤ Hydraulic components are worn.

⑥ Water demand has increased.

Read Why Does My Well Pump Keep Running?

(4)  The Pump Keeps Tripping

Possible causes include:

① Motor overload

② Low voltage

③ Unstable voltage

④ Phase loss

⑤ Cable faults

⑥ Motor winding problems

⑦ Pump blockage

⑧ Excessive sand

⑨ Incorrect protection settings

Read Why Does My Submersible Pump Keep Tripping?

(5)  The Pump Is Overheating

Possible causes include:

① Insufficient motor cooling

② Low water level

③ Motor overload

④ Voltage imbalance

⑤ Frequent starting

⑥ Mechanical friction

⑦ Incorrect operating point

Read Why Is My Well Pump Overheating?

(6)  The Pump Produces Abnormal Noise

Possible causes include:

① Worn bearings or bushings

② Damaged impellers

③ Sand or debris

④ Shaft problems

⑤ Hydraulic instability

⑥ Mechanical contact

Read Why Is My Well Pump Making Noise?

(7)  The Pump Is Vibrating

Possible causes include:

① Impeller imbalance

② Shaft wear

③ Bearing or bushing wear

④ Hydraulic instability

⑤ Pump contact with the well casing

⑥ Internal component damage

Read Why Is My Well Pump Vibrating?

(8)  The Pump Has Low Pressure

Possible causes include:

① Incorrect pump selection

② Worn impellers or diffusers

③ Falling water level

④ Rising-pipe leakage

⑤ Pipeline leakage

⑥ Incorrect valve position

⑦ Excessive system resistance

Read Why Is My Well Pump Pressure Low?

10. How Long Does a Submersible Well Pump Last?

There is no single service-life number that applies to every submersible well pump.

Pump life depends on:

① Pump quality

② Hydraulic selection

③ Operating hours

④ Number of starts

⑤ Water quality

⑥ Sand content

⑦ Pump material

⑧ Motor cooling

⑨ Voltage stability

⑩ Installation quality

⑪ Maintenance practices

A correctly selected pump operating near its intended duty point will generally experience less stress than a pump that is:

① Continuously overloaded

② Operated at an unsuitable flow

③ Operated at an unsuitable head

④ Exposed to excessive sand

⑤ Operated with poor motor cooling

⑥ Operated under unstable voltage

Read How Long Does a Submersible Well Pump Last?

11. When Should You Repair or Replace a Well Pump?

Not every pump problem requires complete pump replacement.

Consider Repair When:

① The fault is limited to replaceable components.

② The motor remains in good condition.

③ The main hydraulic components are serviceable.

④ Spare parts are available.

⑤ Repair cost is reasonable.

⑥ The original pump remains suitable for the duty point.

Consider Replacement When:

① Hydraulic components are severely worn.

② The motor has repeated failures.

③ Repair cost is close to replacement cost.

④ The original pump is incorrectly sized.

⑤ Project requirements have changed.

⑥ Pump efficiency has significantly decreased.

⑦ Spare parts are unavailable.

⑧ Serious corrosion has affected structural integrity.

Before making a decision, compare:

① Repair cost

② Expected service life after repair

③ Pump efficiency

④ Energy consumption

⑤ Operating risk

⑥ Downtime cost

Read When Should You Repair or Replace a Well Pump?

12. What Information Should You Provide for Pump Selection?

Accurate operating information helps the pump manufacturer select a suitable model.

Provide the following information where possible.

(1) Hydraulic Requirements

Provide:

① Required flow rate

② Required total head

③ Required discharge pressure

(2)  Well Information

Provide:

① Total well depth

② Static water level

③ Dynamic water level

④ Well casing diameter

⑤ Planned pump installation depth

⑥ Well recovery rate, if known

(3)  Pipeline Information

Provide:

① Rising-pipe diameter

② Rising-pipe length

③ Surface-pipeline diameter

④ Surface-pipeline length

⑤ Discharge elevation

⑥ Required outlet pressure

(4)  Water Conditions

Provide:

① Water quality

② Sand concentration

③ Sand particle size

④ Water temperature

⑤ pH

⑥ Chloride concentration, where applicable

⑦ Water-analysis report, if available

(5) Electrical Information

Provide:

① Voltage

② Frequency

③ Single-phase or three-phase power

④ Available starting method

⑤ Generator or transformer information, where applicable

(6) Application Information

Provide:

① Pump application

② Required pump material

③ Daily operating hours

④ Continuous or intermittent operation

⑤ Special project requirements

If total head is unknown, provide the complete well, pipeline, pressure, and elevation information.

The pump manufacturer can then calculate the system requirement.

13. Frequently Asked Questions

(1)  Is a Larger Submersible Well Pump Better?

No.

A larger pump may:

① Deliver excessive flow

② Lower the dynamic water level

③ Consume more energy

④ Operate outside its suitable range

⑤ Increase sand intake

The pump should match:

① Required duty point

② Sustainable well yield

(2)  Can a Submersible Well Pump Run Continuously?

A correctly selected pump may operate for long periods.

However, you should confirm:

① Motor cooling

② Water level

③ Pump operating point

④ Motor duty requirements

⑤ Voltage stability

⑥ Manufacturer recommendations

(3)  Can a Well Pump Run Dry?

Dry running can damage many submersible pumps.

Where water levels may fluctuate, consider:

① Water-level protection

② Dry-run protection

③ Suitable monitoring equipment

④ Automatic pump control

(4)  How Deep Should the Pump Be Installed?

The pump should normally:

① Remain below the lowest expected dynamic water level.

② Maintain a suitable distance from the bottom of the well.

The exact installation depth depends on:

① Well design

② Water level

③ Seasonal water variation

④ Sand conditions

⑤ Pump configuration

(5) Is Stainless Steel Better Than Cast Iron?

Not always.

Consider cast iron when:

① Water conditions are suitable.

② Corrosion risk is low.

③ Cost control is important.

Consider stainless steel when:

① Water is corrosive.

② Chloride levels are higher.

③ Better corrosion resistance is required.

④ The project specifies stainless steel.

⑤ Longer corrosion resistance is expected.

The final selection should be based on actual water chemistry.

(6)  How Do I Select Pump Flow and Head?

Remember one simple rule:

Flow depends on water demand. Head depends on system resistance.

Both values must be checked together on the pump curve.

(7)  Can I Select a Pump Based Only on Well Depth?

No.

Well depth alone is not enough.

You should also know:

① Dynamic water level

② Required flow

③ Pipeline losses

④ Discharge elevation

⑤ Required outlet pressure

(8) What Causes a Well Pump to Wear Quickly?

Common causes include:

① High sand content

② Incorrect pump selection

③ Operation outside the recommended range

④ Poor motor cooling

⑤ Frequent starting

⑥ Corrosive water

⑦ Unstable voltage

⑧ Incorrect installation

14. Explore SLAPK Submersible Well Pumps

SLAPK provides submersible well pumps for:

① Deep-well water extraction

② Agricultural irrigation

③ Industrial water supply

④ Municipal water projects

⑤ Mining applications

⑥ Engineered water-transfer systems

Available pump configurations include:

① Flow ranges

② Head ranges

③ Pump diameters

④ Motor powers

⑤ Voltages

⑥ Frequencies

⑦ Pump materials

Explore the SLAPK Submersible Well Pump Range.

For corrosive water and special material applications, view our Stainless Steel Submersible Pump Range.

For pump selection support, please provide:

① Required flow

② Required head

③ Total well depth

④ Dynamic water level

⑤ Well diameter

⑥ Water conditions

⑦ Voltage

⑧ Frequency

⑨ Application

The SLAPK engineering team can recommend a suitable pump according to the actual operating conditions.