Shallow Well Pump Low Pressure: A Comprehensive Guide

Shallow well pumps are a popular choice for homeowners and small-scale agricultural operations that rely on groundwater for their water supply. However, these pumps can sometimes experience low-pressure issues, which can be frustrating and disruptive. In this comprehensive guide, we’ll explore the common causes of shallow well pump low pressure and provide detailed, technical solutions to help you troubleshoot and resolve the problem.

Causes of Shallow Well Pump Low Pressure

1. Faulty Pressure Tank

One of the most common causes of shallow well pump low pressure is a faulty pressure tank. The pressure tank plays a crucial role in maintaining the desired water pressure by storing a reserve of pressurized water. If the tank’s bladder is damaged or the air pressure is not properly adjusted, it can lead to a sudden drop in water pressure.

Technical Specifications:
– Pressure tank size: Typically ranging from 10 to 80 gallons, depending on the pump’s flow rate and water usage requirements.
– Bladder material: Usually made of butyl rubber or other durable materials.
– Air pressure: The tank’s air pressure should be 2-3 PSI lower than the pump’s cut-in pressure, typically between 28-38 PSI.

2. Malfunctioning Pressure Switch

The pressure switch is responsible for turning the pump on and off based on the water pressure in the system. If the pressure switch is not functioning correctly, it can cause the pump to cycle on and off erratically, leading to low-pressure issues.

Technical Specifications:
– Pressure switch range: Typically between 20-60 PSI, with a differential of 10-20 PSI.
– Switch type: Mechanical or electronic pressure switches are commonly used in shallow well pump systems.
– Switch adjustment: The pressure switch should be adjusted to the manufacturer’s recommended settings for optimal performance.

3. Damaged Foot Valve

The foot valve is a one-way valve installed at the bottom of the well, preventing water from flowing back into the well when the pump is turned off. If the foot valve is damaged or clogged, it can cause a loss of prime and result in low water pressure.

Technical Specifications:
– Foot valve material: Commonly made of brass, stainless steel, or plastic.
– Foot valve size: Typically matching the diameter of the well casing or suction pipe, usually ranging from 1 to 2 inches.
– Foot valve design: May feature a screen or filter to prevent debris from entering the pump.

4. Faulty Check Valve

The check valve is another critical component in a shallow well pump system, as it prevents water from flowing back into the well when the pump is turned off. A malfunctioning check valve can lead to pressure loss and water hammer issues.

Technical Specifications:
– Check valve material: Brass, stainless steel, or plastic are common materials.
– Check valve size: Matching the diameter of the discharge pipe, typically ranging from 1 to 2 inches.
– Check valve type: Spring-loaded or swing-type check valves are commonly used in shallow well pump systems.

5. Insufficient Well Depth or Clogged Well Point

In some cases, the low pressure in a shallow well pump system can be attributed to the well itself. If the well is not deep enough or the well point (the perforated pipe at the bottom of the well) is clogged with debris, it can restrict the flow of water into the pump, leading to low pressure.

Technical Specifications:
– Well depth: Shallow wells are typically less than 25 feet deep, although some models can handle depths up to 100 feet.
– Well casing diameter: Commonly ranging from 2 to 6 inches, depending on the pump size and water demand.
– Well point design: Perforated or slotted pipe, with a screen or filter to prevent debris entry.

DIY Tips for Addressing Shallow Well Pump Low Pressure

1. Check the Pressure Tank:
2. Ensure the air pressure in the tank is 2-3 PSI lower than the pump’s cut-in pressure.
3. Use a tire pressure gauge to measure the tank’s air pressure and adjust it accordingly.

4. If the bladder is damaged, the tank may need to be replaced.

5. Inspect the Foot Valve:

6. Disconnect the suction pipe and visually inspect the foot valve for debris or damage.
7. Clean the foot valve or replace it if necessary.

8. Ensure the foot valve is properly seated and sealed at the bottom of the well.

9. Examine the Check Valve:

10. Locate the check valve in the discharge line and inspect it for any signs of wear or damage.
11. Test the check valve by manually opening and closing it to ensure it is functioning correctly.

12. Replace the check valve if it is not operating properly.

13. Test the Pressure Switch:

14. Disconnect the pressure switch and use a multimeter to test its functionality.
15. Adjust the pressure switch settings according to the manufacturer’s recommendations.

16. Replace the pressure switch if it is not operating within the specified pressure range.

17. Measure the Well Depth and Inspect the Well Point:

18. Use a well depth sounder or tape measure to determine the depth of the well.
19. If the well is not deep enough, consider drilling a deeper well or installing a deeper well point.
20. Inspect the well point for any signs of clogging or obstruction and clean or replace it if necessary.

By following these DIY tips and addressing the specific technical issues related to shallow well pump low pressure, you can effectively troubleshoot and resolve the problem, ensuring a reliable and consistent water supply for your home or business.

References:
– Troubleshooting a Shallow Well Pump with Low Pressure
– Shallow Well Pump Pressure Drop
– Recommended Pressure for a Bladder Tank