Shallow Well Pump Head: A Comprehensive Guide for Optimal Performance

The term “shallow well pump head” refers to the vertical distance between the water level in a well and the point where the water is discharged, typically at the ground surface. This height is a crucial factor in determining the performance of a shallow well pump, as it directly impacts the pressure and flow rate of the water being pumped.

Understanding Shallow Well Pump Head

For a shallow well pump, the head is usually measured from the static water level in the well to the discharge point, which could be a pressure tank or a direct outlet. The head can be affected by several factors, including:

1. Well Depth: The depth of the well can influence the static water level, which in turn affects the pump head.
2. Static Water Level: The depth of the water in the well when the pump is not running, also known as the static water level, is a key factor in determining the pump head.
3. Elevation Difference: The elevation difference between the well and the discharge point can impact the overall pump head.

Calculating Shallow Well Pump Head

To calculate the shallow well pump head, you’ll need to measure the following:

1. Static Water Level: Measure the distance from the ground surface to the static water level in the well.
2. Discharge Point Elevation: Measure the elevation of the discharge point, which could be a pressure tank or a direct outlet.
3. Well Depth: Measure the total depth of the well.

The shallow well pump head can then be calculated using the following formula:

Pump Head = Static Water Level + Discharge Point Elevation - Well Depth

For example, if the static water level is 20 feet, the discharge point elevation is 5 feet, and the well depth is 30 feet, the pump head would be:

Pump Head = 20 feet + 5 feet - 30 feet = -5 feet

In this case, the negative pump head indicates that the discharge point is lower than the static water level, which means the pump will not be able to lift the water to the desired height.

Selecting the Right Shallow Well Pump

When selecting a shallow well pump, it’s essential to consider the pump’s performance curve, which typically includes data on flow rate (GPM) and head. This information allows you to choose a pump that can deliver the required flow rate at the specific head for your application.

Here are some key factors to consider when selecting a shallow well pump:

1. Flow Rate: Determine the desired flow rate (GPM) based on your water usage requirements.
2. Pump Head: Calculate the shallow well pump head using the formula provided earlier.
3. Pump Performance Curve: Match the pump’s performance curve to your flow rate and head requirements.
4. Pump Type: Choose the appropriate pump type, such as a centrifugal or jet pump, based on your well depth and water needs.
5. Power Source: Decide on the power source, such as electric or gasoline-powered, based on your available resources and preferences.

Measuring Shallow Well Pump Performance

To measure the performance of a shallow well pump, you can use the stopwatch method demonstrated in the video “How to Measure Your Well Pump GPM”. This method requires knowledge of the pressure tank’s drawdown, which is the difference between the tank’s full capacity and the point at which the pump turns on.

By measuring the drawdown and the time it takes to refill the tank, you can calculate the pump’s flow rate (GPM) using the following formula:

Flow Rate (GPM) = Drawdown (gallons) / Time (minutes)

For example, if the drawdown is 21.7 gallons and it takes 1 minute to refill the tank, the flow rate would be:

Flow Rate (GPM) = 21.7 gallons / 1 minute = 21.7 GPM

This information can then be used to evaluate the pump’s performance and ensure it meets your water needs.

Shallow Well Pump Head Considerations for DIY Projects

In the DoItYourself.com forum post “Cheaply drawing water from a shallow well”, a user is seeking a low-cost solution to pump water from a 17-feet deep, 36-inch diameter well with around 3 feet of water. The user is considering using a cheap pump like the one from Harbor Freight, which is suitable for continual submersion.

When working with a shallow well, it’s essential to carefully consider the pump head to ensure the pump can effectively lift the water to the desired discharge point. In this case, the shallow well depth of 17 feet and the 3 feet of water would result in a pump head of approximately 14 feet (17 feet – 3 feet = 14 feet).

It’s important to select a pump that can handle this head and provide the necessary flow rate for your water needs. Additionally, factors such as the well diameter, water quality, and any elevation changes between the well and the discharge point should be taken into account when choosing the appropriate shallow well pump.

Conclusion

The “shallow well pump head” is a critical factor in determining the performance of a shallow well pump. Understanding the relationship between the pump’s flow rate and head allows you to select a pump that can meet your specific water needs while considering factors such as well depth, static water level, and discharge point elevation.

By following the guidelines and calculations provided in this comprehensive guide, you can ensure that your shallow well pump is operating at optimal efficiency, delivering the necessary flow rate and pressure to meet your water requirements.

Reference:
– Terry Love Plumbing Advice Forum
– How to Measure Your Well Pump GPM (YouTube)
– Cheaply drawing water from a shallow well (DoItYourself.com)