Understanding water pumping engineering basics
So, you've checked with your state and found out that pumping water is perfectly legal in your area. You have a great source of water on your property and you've figured out exactly what you want to use it for. Now you're ready to learn HOW to pump water from it.
One little caveat before we dive in—this stuff can get really technical, so be prepared to exercise the left side of your brain for the next several paragraphs. But regardless of if you're installing the system yourself or are hiring a contractor to do it for you, knowing how it all works is extremely beneficial as it will help you better maintain, modify, and troubleshoot it in the future. Plus, if you are hiring someone, the more you know about the process, the better for everyone.
And if you are DIY from the ground up, all the details are extremely important in a water pumping system. An incorrectly-sized pump will either not provide any water at all, or worse, can cause long-term, very expensive damage. So, you can't cut corners.
OK, onward.
Flow Rate and Pressure
The first basic concept to understand is the relationship between flow rate and pressure.
Flow rate can be described as the volume or “amount” of water that comes through a water pumping system. A high flow rate is associated with more water and a low flow rate is associated with less water. Flow rate is expressed in gallons per minute or GPM.
Pressure is associated with the amount of force within the water system. From a practical perspective, a high-pressure shower is much more desirable than a low-pressure shower.
Ultimately, a water system with high-pressure and a high-flow rate is generally more desirable. The problem that pump science has to overcome is that there is a lot of resistance that prevents most water systems from achieving the target pressure and flow rate. This resistance can come in the form of gravity, friction, and distance of which water has to travel.
The goal of the water pump is to overcome this resistance and provide the user with the desired amount of water pressure and flow. But finding just the right pump is crucial. Too weak of a pump will result in poor pressure and flow or none at all. Too strong of a pump can result in damage and a shortened pump life.
The objective for the homeowner is then to find the right type of pump by calculating the exact amount of pressure and flow the system requires.
This is why it's important to determine the purpose of the water use upfront. A sprinkler system will have different pressure and flow requirements than a kitchen faucet.
How to size a pump
In pump engineering, flow rate is expressed at GPM and pressure is expressed as TDH. These two measurements will be unique to your system and we'll work through how to calculate them as you'll need them when you choose a pump.
Flow rate: Gallons Per Minute (GPM)
Faucet / Alicja / Pixabay
Flow rate is the overall amount of water that will flow through the system and out of the fixtures—a faucet, showerhead, garden hose, etc. Flow rate is expressed in GPM or gallons per minute in the United States. In other places, it may be expressed as liters per minute. Regardless of which unit of measurement is used, the concept remains the same.
The average flow rate for a home’s internal water system is typically between 6-12 gallons per minute, depending on the number of faucets, showers, and appliances being used. A larger home with more bathrooms and water fixtures will require a higher flow rate than a smaller home with fewer fixtures.
A single fixture flows at a rate of 1-2 GPM. By counting the number of fixtures, you can get a rough estimate of the flow rate demand for your home or cabin.
Determining your exact flow rate demand can be a very precise process that goes beyond the scope of this article. There are formulas to help calculate the exact number which may be necessary for large home applications. But for the purposes of drawing water for a small cabin or cottage, a ballpark range should do.
Once you've determined what your flow rate is, keep this number for later.
Pressure: Total Dynamic Head (TDH)
Total Dynamic Head Diagram / watermission.org
Measuring TDH is a bit more complex as it involves several critical steps.
As the pump creates pressure within the system, it needs to overcome a certain amount of resistance in order to provide the desired amount of water pressure at the fixture outlet. And because resistance comes in the form of various factors such as air pressure, pipe length, and friction, measuring it requires the sum of all of these factors.
The total sum of this resistance is called TDH or Total Dynamic Head.
Because TDH is a collection of different units of measurement, the simplest way to measure TDH is by feet.
There are 3 components that make up the Total Dynamic Head. They are the vertical lift (often called static head), friction loss, and operating pressure.
Vertical lift / Static head
Vertical Lift Diagram / watermission.org
Vertical lift, or static head, refers to the amount of pressure the pump will have to overcome when pushing water upwards. Because water is heavy, it creates a strong downward pressure on the pump, similar to how divers experience pressure in their eardrums as they descend further toward the ocean floor.
Vertical lift measures the total vertical distance the water must travel from the outlet of the pump to the highest part of the water system. It is important to note that vertical pressure doesn’t account for any horizontal distance in the water system, nor does it account for moving water. It only measures vertical distance while the water is perfectly still which is why it's also referred to as "static" head. Water in motion causes changes in pressure which we’ll account for later.
In order to measure vertical pressure, simply measure the distance from the pump outlet to the highest point of the water system. This distance is measured in units of feet. Keep this number for later calculations.
Friction loss
Friction Loss Diagram / watermission.org
Water in motion causes changes in pressure. As water moves through pipes, pressure is lost as it comes into resistance with the pipe walls and corners. The width and material of the pipes as well as the total distance that water has to travel through are all major factors in calculating friction loss.
This “friction” causes water to lose pressure and must be accounted for as the pump will need to work harder to compensate for it.
In order to account for friction loss, you’ll need to reference a friction loss chart or calculator. But before that, you’ll need to know the flow rate and the total length and diameter of your exit pipe. Some friction loss calculations involve as much detail as counting all the corners and right angles in the pipe.
Some of these numbers might not be available—and you'll just have to work with what you have. But as with any aspect of pump engineering, the more precise the calculations, the more likely the pump system works to your benefit.
If you’re purchasing a pump to add to your home or cabin's existing plumbing system, check with the original building plans to find out the length and diameter of your pipes—rather than having to measure everything yourself.
But if you’re designing your water system from the ground up, say for a small cabin or an outdoor irrigation system, the selection of your pipe materials will be a major factor. Larger-diameter PVC pipes move water much better than smaller copper pipes and rubber hoses. Consider 2" PVC pipes for better flow.
Once you’ve gathered these numbers, reference the friction loss chart to get the total friction loss number in units of feet. Save this number for later.
Operating pressure
Finally, operating pressure simply refers to the desired amount of water pressure at the point of use. Generally, people like a significant amount of pressure especially when using showerheads and kitchen faucets. Other appliances such as sprinkler systems or pressure tanks will have a specific operating pressure that must be met.
The operating pressure is largely preferential in most cases, but on average, the final operating pressure among all the fixtures usually ranges between 30 psi to 80 psi for most homes. But, like vertical lift and friction loss, we’ll need this number expressed in units of feet.
To convert from psi to feet, use this calculator. Or simply multiply the psi by 2.31.
Now that you have the numbers that make up the TDH, simply add them together.
Add the vertical lift, friction loss, and operating pressure together, in units of feet.
This final number is your Total Dynamic Head. It accounts for all the potential resistance that a pump will encounter when attempting to push water through the system.
Final Step: The Pump Curve
If you've made it this far, you should be very proud of yourself. These basic pump engineering concepts aren't easy to grasp and people pay lots of money to learn them.
But again, whether you're hiring someone to install the pump for you or you're the DIY type, understanding how your pumping system works will reap long-term benefits overall.
So, moving on.
Now, you should have your TDH as expressed in feet and your flow rate as expressed in GPM.
You'll need these two numbers when selecting a pump.
Pump manufacturers will display a lot of information about the pump such as horsepower, voltage, max PSI, and even flow rate in GPM. One of the misconceptions that new pump buyers usually have is that a pump with a certain GPM or PSI rating will produce that exact GPM or PSI in practice.
This is simply not true. Pump manufacturers make a variety of pumps in order to meet the various requirements that homeowners and consumers may have. The GPM rating on a pump will only produce that much under specific conditions. But it may very well be under or over that number.
As a buyer, what you’ll need to pay attention to most is the manufacturer's pump curve chart. Referencing your TDH and GPM, you’ll be able to determine which pump will meet your exact needs.
Here's an example of what a pump curve looks like for an above-ground jet pump.
Each pump will have its own performance curve unique to its specifications.
Notice the TDH scale on the left side of the chart and the GPM scale on the bottom then find where your numbers lie on each scale.
Draw a horizontal line from your TDH number on the left and a vertical line from the GPM number on the bottom. If these two lines meet at any point on the performance curve then this pump will meet your requirements. Ideally, you'll want the point to meet somewhere in the middle of the curve for optimum efficiency.
If the two lines meet anywhere above or below the curve, this specific pump will not perform to your requirements. You'll need to check out another pump.
Pump curves can look confusing. Luckily, a sales associate should be able to assist you in reading the curves and selecting the right pump for your needs. They’ll be glad you already have the TDH and GPM handy.
FAQs
Ultimate Guide to Pumping Water from a River, Lake, or Creek? ›
Understanding water pumping engineering basics
So, you've checked with your state and found out that pumping water is perfectly legal in your area. You have a great source of water on your property and you've figured out exactly what you want to use it for.
Understanding water pumping engineering basics
So, you've checked with your state and found out that pumping water is perfectly legal in your area. You have a great source of water on your property and you've figured out exactly what you want to use it for.
Sprinkler pumps are used to pump water from lakes, ponds, etc. to lawn sprinklers for irrigation. Pool cover pumps are used to remove standing water and prevent damage to expensive pool covers. Drill pumps are used in conjunction with a drill to unclog sinks, drains or washing machines.
What is the best way to pump water from a stream? ›The best way to draw water from a stream is to build a U-shaped “channeled” water catchment. This is just a wooden trough that has a screen that the water can drain into. Underneath the screen is a pipe. A ¾ “ black poly pipe would work fine.
Is it OK to drink water from a creek? ›Never drink water from a natural source that you haven't purified, even if the water looks clean. Water in a stream, river or lake may look clean, but it can still be filled with bacteria, viruses, and parasites that can result in waterborne diseases, such as cryptosporidiosis or giardiasis.
What kind of pump do I need to draw water from a lake? ›Lawn pumps are used when lake, pond, or municipal water is pumped for irrigation. Common uses include pumping water from a lake to power lawn or garden sprinklers.
How do you prime a water line from a lake? ›- Make sure the power is turned off. Never leave a pump plugged in while you're working on it. ...
- Gain access to the pump system. ...
- Check for damage. ...
- Test a hose. ...
- Open the relief valves. ...
- Attach the hose. ...
- Turn on the water and wait for it to enter the tank. ...
- Turn the power on.
A submersible pump pushes water to the surface by converting rotary energy into kinetic energy into pressure energy. This is done by the water being pulled into the pump: first in the intake, where the rotation of the impeller pushes the water through the diffuser. From there, it goes to the surface.
What pumps are used for lakes? ›Centrifugal pumps are used to pump from reservoirs, lakes, streams and shallow wells. They also are used as booster pumps in irrigation pipelines. All centrifugal pumps must be filled completely with water or “primed” before they can operate.
What size pump do I need for my stream? ›Waterfall Pump Flow Rates
For waterfalls and streams, your pump should pump at least 100 gallons per hour for every inch wide the waterfall is. For more noise and "white-water" from your falls, increase the flow rate to 200 gallons per hour per inch of waterfall width.
What is the best flow for water pump? ›
A higher flow rate will equal a bigger tank and more powerful pump. Bear in mind, a good flow rate for most taps is around 15 LPM.
Can you use a submersible pump in a lake? ›The use of submersible pumps in lakes, rivers, and other water bodies is becoming increasingly common. A submersible or deep well pump provides greater capacity and pumping capability at greater distances and elevations than a common suction or jet pump.
How do you pump water from a small stream? ›To allow your pump to draw water from a shallow stream, you will need to use different techniques. One such is to create a small well that deepens the bed of the stream, thus giving you more room. Another technique involves placing a cover just above the intake to prevent it from drawing in air and creating a vortex.
Can you really pump water without any electricity? ›Spiral pumps work without fuel or electricity, since the needed energy is supplied by flowing water (preferably a flow velocity faster than 1 m/s). The spiral pump saves up to 70% of overall lifetime costs compared to diesel pumping. The spiral pump requires no operation costs and it is environmentally friendly.
What is the cheapest way to pump water from a well? ›The sleeve bucket is the simplest and cheapest way to get water from your well without electricity. Also known as torpedo or cylinder buckets, the modern-day “well bucket is simply a long, skinny bucket that can be lowered into the narrow confines of a well casing to bring water to the surface.”
How do you purify creek water for drinking? ›- Boiling. If water is cloudy, allow to settle, then skim the clean water above the sediment. ...
- Disinfect by using: Unscented household chlorine bleach or iodine (useful against most, but not all, harmful viruses or bacteria. ...
- Filtering.
Look for animal tracks, swarms of bugs, and green vegetation nearby—if other living things are drinking from it, you probably can, too. Most of what makes water dangerous isn't visible, and that's true of taps as well as streams.
How do you naturally purify river water? ›Boiling Water: This is the most effective method to kill all bacteria. Just maintain a rolling boil for 1 minute (depending on elevation), let cool and you're good to go. Here's more about purifying water by boiling. Pros: No special gear needed.
What are the three types of water pumps? ›There are three basic types of pumps: positive-displacement, centrifugal and axial-flow pumps. In centrifugal pumps the direction of flow of the fluid changes by ninety degrees as it flows over an impeller, while in axial flow pumps the direction of flow is unchanged.
Do you need a pressure tank for a lake pump? ›Pumps will work without a pressure tank, as there are automatic pumps fitted with a constant pressure controller so these pumps start and start on demand.
Are electric water pumps better than mechanical? ›
Are Electric Water Pumps Better Than Mechanical? Electric water pumps have fewer wearable parts than mechanical water pumps. Mechanical pumps are driven by a pulley with a belt or chain. They also have seals and bearings that can wear out over time.
What happens if you don't prime a water pump? ›Priming maintains the pump's functionality because water, or the pumped fluid, acts as a coolant which prevents the pump from overheating. If you don't fill the pump with fluid, it will run dry, which leads to mechanical seal failure or damage to the pump's components.
What stops lakes from draining? ›For a lake to keep its water over time, it has to be replenished. There are both natural and man-made lakes. The main way that water gets into reservoirs and man-made lakes is from the rivers and streams that were dammed to create them.
Can I pump water out of a lake? ›Assuming you can have a pump, a basic jet pump may do the trick. One of our staff members has a pump which sits on her dock with a hose and filter tip extending into the lake. The other end of the pump is connected to a one-way valve and then a hose. She pushes it on and voilà, the garden is watered!
How far should a submersible pump be from the bottom? ›Well depth plays a role in pump placement. Pumps should never be set directly at the bottom of a well. It is usually best to place the pump 10 to 20 feet up from the bottom of the well.
How long can you leave a submersible pump running? ›Can Submersible Pumps Run Continuously? Yes, you can run a submersible pump continuously for as long as you require if you have the suitable source of water. Saying that, it is imperative that you do not run a submersible pump dry.
What is the most commonly used water pump? ›The two most common types of pumps used for pumping water are centrifugal pumps and positive displacement pumps.
What water pump do I need? ›So, to determine what flow rate you need, simply divide the total water capacity of your pond by 60. For example: With a 7000 litre fountain, simply divide 7000 by 60 = 116.6. In this case, you need a pump with a flow rate above 116.6/LPM.
What is the difference between a submersible and jet pump for a lake? ›Although jet pumps can still handle depths of several hundred feet, submersible pumps are typically more effective at greater depths. By moving the pump down the well, the pump no longer lifts the water but, rather, pushes it upward. A submersible pump won't work, however, unless it's completely submerged in liquid.
What size of pump do I need to lift water 250 feet? ›3/4 HP - 1 HP Submersible Sump Pumps
In addition, if you have an installation where you need a high vertical lift or head (20-30 feet) and/or a long horizontal run (150-250 feet), 3/4 - 1 HP pumps provide the additional power needed to pump that water.
How deep should a stream be? ›
Be sure to check the stream's depth from the skimmer. The stream should be 8” – 12” deep, which will allow fish to swim up to the waterfalls.
How strong of a pump do I need? ›Minimum Pump Size
Water needs to circulate through the filter at least once every 2 hours. This means that if you have a 1,000-gallon pond, you need a pump that can produce at least 500 gallons per hour or GPH. If you have fish, then it is best to double the pump's capacity to ensure that your water stays clean.
5 gpm (two fixtures running simultaneously at 2.5 gpm) is a good estimate of peak demand, for the typical household. Water wells that reliably yield 5 gpm should be able to meet peak and daily needs for most residences. Wells yielding less than 5 gpm, however, are sometimes the only water source available.
What psi should I pump water? ›Normal psi for a home pipe system is between 30 and 80 psi. While you don't want the psi to be too low, it violates code to be above 80. Instead, you should aim for a psi that's between 60 and 70.
What is the most efficient water pump design? ›The most efficient pump design is a centrifugal pump. A centrifugal pump is a type of pump that uses the force of rotation to move fluid through the device. Centrifugal pumps are generally more efficient than other types of pumps because they can move a greater amount of fluid with each turn of the impeller.
What is an alternative to a submersible well pump? ›There are also centrifugal and hand pumps that work best for homes with more shallow wells where a jet or submersible well pump may not work, or on properties that work off the grid. These pumps sit above ground, drawing water out through a single pipe, kind of like a straw.
Can I use a submersible pump in a river? ›It is not recommended to use borehole submersible pumps in a river or dam, instead of a standard centrifugal pump and motor. However, submersible pumps can be used in certain instances, as borehole submersible pumps do not get water damage unlike standard electrical motors if flooded.
Can you pump water from a creek? ›Ram pumps work by using the downward flow of a stream or river to build pressure within a collection chamber. When enough pressure has been built up, water can be pushed through an outlet much like any electric-powered water pump.
Will a ram pump work in a river? ›Generally, streams, rivers or springs can be used as a source to operate these pumps, but a sufficient flow/capacity is needed to operate them, as a large portion of the water serves as an energy source that then exits below the pump and returns to the water source.
How deep will a hand pump pump water? ›The pumping mechanism is in the pump cylinder and pulls water up by creating suction. Deep well hand pumps can lift water from depths greater than 25 feet. The deep well hand pumps accomplish this by lowering the pumping mechanism into the well.
How do you get water from a creek? ›
The best way to draw water from a stream is to build a U-shaped “channeled” water catchment. This is just a wooden trough that has a screen that the water can drain into. Underneath the screen is a pipe. A ¾ “ black poly pipe would work fine.
What is the best way to get water from a well without electricity? ›Hand pump
Some styles of hand pump can be mounted on a well without disrupting your existing electric well pump, and be used as a backup to deal with power outages. Do your homework to find the right pump, as some pumps will only pull water up a few feet and others can pull water out of a 200-foot well.
If the well is less than 25 feet deep, use a shallow well jet pump. If the well is 25' to 110', use a deep well jet pump. And, if the well is 25' to 400' deep, use a 4" submersible pump. A jet pump pulls water and a submersible pump pushes water upward.
What is the life expectancy of a well water pump? ›The average lifespan of a well pump is 15-25 years, and you will typically start to notice more issues with your pump as it ages like an increase in repairs, changes in water pressure or increasing utility costs.
How long should a pump for water well last? ›The lifespan of a well pump is usually between 8 and 15 years, but how long yours lasts can depend on the way you use it and the type of pump you choose. The size and quality of the motor in the pump can affect how long it lasts. A pump with a larger, more durable motor should last longer if you care for it well.
Can I use creek water to water my garden? ›River or Creek
If the garden is located near a flowing river or stream, it may be possible to pump water to the garden. This will require a properly sized pump, power for the pump (electricity or gasoline), filter and enough water pipe to run from the water source to the garden.
But if the creek water is fresh water it is as good as the tap water. Most tap waters are either treated or less saline which is good for most plants.
Can you use a creek to fill a pond? ›If the stream is small enough that it only fills after a heavy rain, he suggests finding a different water source. Lusk says pumping water from a nearby creek or river can cause unwanted fish could hitch a ride into your pond.
Can you filter water from a creek? ›It's possible to filter river water for the purpose of removing contaminants and effectively purifying the water.
Can you boil creek water and make it safe? ›1. Boil. If you don't have safe bottled water, you should boil your water to make it safe to drink. Boiling is the surest method to kill disease-causing germs, including viruses, bacteria, and parasites.
Do creeks run dry? ›
The authors report that 51–60% of the world's streams do not flow for at least one day per year, and that 44–53% of global stream length is dry for at least one month (about 30 days) each year.
Does creek water have nutrients? ›Nutrients are present naturally in lakes and streams, but human activity has greatly increased the amounts going into surface waters. Background levels of nitrogen and phosphorus are generally quite low and are normally measured in milligrams per liter.
Can you pump water from a stream? ›To allow your pump to draw water from a shallow stream, you will need to use different techniques. One such is to create a small well that deepens the bed of the stream, thus giving you more room. Another technique involves placing a cover just above the intake to prevent it from drawing in air and creating a vortex.
How do you get water from a river? ›...
There are three methods of developing streams and rivers and obtaining clean river water:
- Intake through infiltration wells and galleries;
- Direct intakes connected to mechanical pumps; and.
- Direct intakes using gravity flow.
If you're filling your pond using a household water tap, you're probably looking at a max flow rate of 2.2gpm, which is about 132 gallons per hour. At this rate, running 24 hours per day, it would take 17 months to fill your pond, not allowing for evaporation, storm events, or other factors.
How do you dam a creek naturally? ›Sand bags and rocks are an easy way to dam a backyard creek. Alternate layers starting on the creek bed spot you want to dam. Stack as high as necessary. Here's another way to dam a creek using lumber.
How do I keep my farm pond full of water? ›Groundwater can help fill a pond, but in most places, this isn't usually enough to completely fill a pond, which means it will need to be supplemented with something else. Natural springs, if available, are an ideal source of water. Nicely flowing springs will keep the pond full of a continuous flow of clear water.