How a Water Well Works: The Ultimate Guide
If you live in a town or city, your drinking water likely comes from a public water system. All you have to do is turn on the tap, and water comes gushing out. But move a few miles out of town, and you’ll realize things can be much different.
People living in rural or remote communities not hooked up to a centralized water system typically get their water through public or private water wells, or what some people describe as “large holes in the ground that store water.” But as you’ll soon discover in this article, there’s a lot more that goes into a water well’s construction and operation than meets the eye.
Water wells are essential to developing a sustainable society, providing a reliable water supply for drinking, cooking, showering, irrigation, etc., even in areas where surface water is scarce (think deserts). And thanks to much-needed advances in plumbing and technology, modern well systems are far more efficient and reliable than those used in ancient and even recent history.
Homeowners no longer have to dig water wells by hand, turn a hand crank to fetch water from the bottom, and transport it in buckets to wherever they need it. They can now enjoy instant access to clean running water throughout their households hands-free, all while escaping those pesky monthly water bills synonymous with city water. But how is all this possible? Where does well water come from, and how does it get to houses, apartments, farms, or businesses?”
Continue reading this ultimate guide to learn what components make up a well system, the mechanics behind how a well works, and everything else you need to know.
What is a Water Well?
A water well is essentially a structure or excavation created in the ground by digging, drilling, or driving deep enough to access the groundwater for extraction. Traditionally, containers, such as buckets, were used to fetch the water mechanically or by hand. However, modern water wells generally use a pump to retrieve water from underground.
How Do Water Wells Get Their Water?
Before we discuss how a well works, you should first know where wells get their water. In a nutshell, well water comes from sources beneath the earth’s surface. When rainwater, melted snow, or water from other forms of precipitation falls on land, it soaks into the ground and moves downwards to fill all the possible cracks or spaces in the soil and rock. The water then settles and becomes groundwater, a renewable resource that makes up about 95% of the world’s freshwater supply.
Groundwater often collects in large water-bearing geological structures called aquifers. Aquifers consist of layers of rock and soil that allow water to flow through their tiny pores. That means groundwater can slowly move from one aquifer to another. Usually, the groundwater follows permeable pathways within individual aquifers from the point of recharge to discharge. It may also undergo filtration, but it can get contaminated when it reaches the earth’s surface.
Whether a well is drilled, dug, or bored, it has one purpose: to reach far enough into the aquifer to access and pump out the water. However, because an aquifer’s location and the amount of water it contains are rough estimates, it can be challenging to know where and how deep a well needs to be.
Types of Water Wells
Digging water wells by hand has become outdated in many places due to automated drilling techniques and new plumbing technologies. These developments have almost eliminated the need for manual-labor methods because, let’s face it, who wants to spend all day hacking the ground with a shovel? In most cases, modern wells are drilled by a truck-mounted drill rig, but there are a few other methods to construct a well:
Dug or Bored Wells
Dug or bored wells used to be constructed by digging a large hole into the ground with a pick, hand shovel, or backhoe below the water table until the incoming water exceeded the digger’s bailing rate. The hole was then lined (or “cased”) with stones, brick, tile, or other material to support the wall and prevent it from collapsing. This lining also blocked surface water from entering the well water supply. The hole was then covered with a cap of wood, stone, or concrete for safety purposes.
Luckily, modern dug wells are dug by power equipment and are usually lined with concrete tiles. These wells usually have large diameters to increase their exposure to the aquifer. They also can go deeper beneath the water table than hand-dug wells.
Modern dug wells can collect water from less-permeable materials, such as clay or sand. However, they are shallow (approximately 10 to 30 feet deep) and lack continuous casing, making them prone to contamination from nearby surface sources. Apart from the high risk of contamination, the low water levels in dug wells mean that if the water table drops below the well bottom, perhaps during a drought, the well may go dry.
Drilled wells are the most common among modern wells. They can be as shallow as 10-60 feet and as deep as 1,000 feet, though industrial drilled wells can exceed depths of 3,000 feet (900 meters).
Drilled wells are constructed using a cable tool (percussion) or air or hydraulic rotary drill rig typically mounted on a trailer, truck, or carriage fitted with powerful drill bits that can drill more than 1,000 feet deep.
During the drilling process, the rotary drill bits chew away at the rock while the percussion bits smash them. However, larger auger bits are used if the wells are penetrating materials consisting of granular materials like sand, clay, and gravel. Still, drilling into such materials requires a casing to prevent collapse and a screen to restrict sediment inflow. The space around the casing is sealed with grouting materials containing neat cement or bentonite clay to prevent contamination from water draining off the surface and down to the casing exterior.
Driven wells are perhaps the most straightforward and most inexpensive wells to construct. These wells are created by driving a small-diameter pipe into the shallow ground. The pipe has a screen or a filter fitted at the bottom to allow water to enter and keep out as much sediment as possible. It also helps keep the water-bearing formation in place.
Usually, driven wells can only be installed in areas with relatively loose soils, such as sand and gravel, and where there’s a shallow water table near the surface. The pipes are driven into the ground or inserted by hand until it reaches the water table. Once the well is deep enough, all the dirt is washed from inside the pipe. A pump is then installed to draw water from the aquifers.
Hand-driven wells are typically about 30 feet deep and 50 feet deep when driven by machine. That means, either way, they are effective in shallow water but can be easily contaminated as they draw water from aquifers near the surface. Worse, they aren’t usually sealed with grout materials.
The Key Components of a Well Water System
A modern residential well system is relatively complex. It comprises several components that combine to pump water from underground sources and allow the water to flow to the surface and throughout your home. In case you’re wondering what these components are, we’ve outlined them and explained their functions below.
· Well Casing
The well casing is a hollow, large-diameter plastic or steel pipe installed to provide the pathway for the water to travel up from the aquifer to the land surface. It also helps maintain the well opening, forms the well’s shape and structure, and supports the well so that loose rock fragments or unconsolidated sand and gravel through which the well has penetrated do not collapse into the well shaft.
Generally, well casings are made of carbon steel, stainless steel, or polyvinyl chloride (PVC) and have a diameter of about five inches. PVC is lightweight, resistant to corrosion, and relatively easy for contractors to install. However, it’s not as resistant to heat as steel, although steel is susceptible to corrosion and scale buildup and can cost more than PVC.
In any case, the casing – along with grout – prevents dirt from entering the well and polluting the water. It also keeps excess water and contaminants from less desirable groundwater out of the well. The most common materials for well casing are concrete, fiberglass, or asbestos cement. However, the local geology often dictates what type of material can be used.
· Well Caps
Well caps are primarily installed to prevent surface pollution, especially bacterial contamination. Bacterial contamination is a common problem that occurs in many private water wells in America. Thankfully, aluminum or thermoplastic well caps provide a water-tight seal to keep debris, insects, small animals, runoff, and other potential contaminants from entering the well system. The cap is usually placed on top of the well casing and includes a vent to control the pressure during well pumping. It also helps prevent overflows from contaminating the well when it’s extended past the flood level.
· Well Screens
Think of the well screen as a filter that traps bits of dirt, rock, sand, and other sediments trying to get into the well. This filtering device is often attached to the bottom of the well casing to prevent excess sediment from contaminating the well while allowing water to pass. The most common well screens are continuous slots, slotted pipes, and perforated pipes.
Continuous slot screens are made of wire or plastic wrapped around a series of vertical rods. This configuration provides consistent, regular slot openings that can be engineered to the particle sizes found in the screened zone. Slotted pipe screens usually have the least open area. However, they feature machine-cut slots into steel or plastic casing at set distances. Perforated pipe screens contain holes or slots drilled into the pipe and perforated in place after the casing is installed. This well screen is usually not efficient for groundwater with lots of sand, gravel, and other sediments, due to the wide openings.
But generally, well screens are built to suit the local geography of the well’s installation site and have specified openings and holes to match the screen filtering capacity. They’re also designed to be placed within the aquifer’s saturated portion to prevent damage if the groundwater elevation drops.
· Pitless Adapter
Pitless adapters are connectors that provide a sanitary and frost-proof seal between the well casing and the waterline. These adapters are connected to the well casing below the frost line to divert water through the side of the adapter to prevent the water from freezing. A check valve is sometimes fitted below the adapter to prevent water from flowing back into the well.
· Well Pump
The well pump is the central component of the well system. It’s responsible for pumping water upward from the aquifer and into the household or designated water system. The two most popular types of well pumps are jet pumps and submersible pumps. Both pumps use a centrifugal force created by spinning rotors, known as impellers, to force the water upwards. The rotors create a vacuum that forces the water upward through the well casing and into the distribution system. The type of pump required for a well system depends on how deep the well is and the amount of water the household requires.
Jet pumps are the most commonly used pumps for shallow wells 25 feet deep or less. This type of pump is mounted above ground and uses a suction pipe to draw water from the well. The suction pipe creates a vacuum with an impeller that drives water through a small nozzle. Because jet pumps use water to pump water, they first need to be primed with flowing water. Shallow well jet pumps are used for wells with a depth of 25 feet, while deep well jet pumps typically go down 150 feet. Deeper wells would require a submersible pump.
Submersible pumps can be used for private wells as deep as 400 feet or more. They are quickly replacing jet pumps because they dedicate most of their energy toward pushing water upward than drawing water from the well to the pump, as is the case with jet pumps. Jet pumps are also less efficient and noisier than submersible pumps. As the name suggests, submersible pumps are submerged deep in the well just under the water level. They have a cylindrical shape, housing the pump motor and a series of impellers that force water up the pump into the drop pipe. Most modern well systems use submersible pumps over other types because of their durability, versatility, and efficiency.
· Pressure Tank
The pressure tank is a crucial component of a well system. It is used to maintain water pressure throughout the system and acts as a reservoir to allow water to be drawn from the tank without the pump cycling on and off every time the water is on. Pressure tank sizes can range from around 40 gallons for domestic use to 21,000 gallons or more for industrial use.
In standard pressure tanks, the pressure is created by pumping water into the tank until the air in the tank is compressed to 40, 50, or 60 psi (pounds per square inch). An air compressor is fitted to maintain an ideal air pressure. When the valve is opened via a faucet, the air pressure in the tank forces water out of the tank and into the pipes for distribution to your shower, kitchen faucet, water heater, dishwasher, and any other water outlet or water-using appliance in your house.
· Pressure Switch and Control Box
Well pumps aren’t designed for non-stop operation. This is especially true for submersible pumps because continuous usage would likely cause unnecessary wear on the pumping mechanism and hike up electricity costs. Luckily, the pressure switch and control box work together with the pressure tank to measure the well system’s water pressure. This ensures the pump only kicks in when the water pressure drops below a specific level.
Conventional well systems have a water pressure range of 60 psi. When the water pressure falls below the minimum range of 40 psi, the pressure switch signals the pump to turn on to bring the water pressure back within range. Once the water pressure is at an ideal level, the pressure switch turns the pump back off.
How a Well System Works
A well system is designed to draw water from the ground and deliver it into the household or a specific water system. Let’s use an example to depict how the system can achieve this.
Example: Your home is connected to a drilled well with a submersible pump in a pitless adapter set up with a pressure tank and pressure switch inside the house.
Here’s how the well system would work:
- When you turn on any faucet or water-using appliance in the house, the water from the pressure tank is pumped to wherever the water is being used, whether the sink, dishwasher, washing machine, or shower. As the water flows throughout the house, the water pressure in the tank naturally drops.
- If the water pressure drops below the minimum 40 psi (indicated by the pressure gauge), the pressure switch signals the pump to turn on. (Most pressure tanks have a pressure range of 40 psi to 60 psi.)
- Impellers in the submersible pump (about 200 feet or so underground) begin to spin rapidly, forcing the water upward through the casing and the pitless adapter.
- As the water is pushed through the waterline and into the house, the pressure tank fills gradually, as shown on the pressure gauge. But before the water enters the tank, there’s a check valve sitting before the pressure gauge to prevent the water from back-flowing.
- Once the pressure tank reaches a maximum of 60 psi, the pressure switch signals the pump to turn off, halting the water flow into the system. The pressure remains at this level until more water is used and eventually drops. Once it drops below 40 psi, the pump kicks on again, and the cycle starts over.
Key Considerations Before Constructing a Well System
If you’re thinking about constructing a well system for your home, there are a few key considerations you need to know before getting started. Following these tips will help you create a good-working well that can provide clean, refreshing water for years to come.
· Get Familiar with the Land
Whether you’re purchasing a home with a well system installed or scouting the area for a place to build, you should familiarize yourself with the land beforehand. You can start by asking well owners in the area about whether they’ve had success or trouble with their systems. The local authorities can also provide detailed information about the groundwater’s condition in the area, how deep they expect a well needs to be drilled, and whether the water level is known to be particularly low at certain times of the year. You’ll also want to ask about the climate because snow, rainfall, flooding, and other elements may cause problems. Another crucial thing to be aware of is nearby factories and other factors that may pose a contamination risk.
· Choose the Most Suitable Location for the Well Site
Choosing the best location for the well site is one of the most crucial decisions you can make before constructing a well system. This particular location not only provides the most water yield but has the least contamination risk. Although finding the location can only be achieved by estimating, a general rule is to make sure it has a high elevation. In areas with heavy rainfall, the rainwater from the higher ground level tends to leach contaminants to the lower ground floor as the water flows downhill. If the well site is in a low-basin area where rainwater collects, there is a high risk of contaminants entering the groundwater through the well.
If your home has a septic tank, ensure the well site is on a higher ground level than the septic tank and at a far distance. Septic tanks are almost always susceptible to leaks, so the contaminants should move away from the well site than towards it. Overall, try to choose a location away from objects and places that can potentially disrupt or contaminate the well, such as barns, streams or creeks, septic tanks, and livestock pens.
· Acquire the Necessary Permits
Well permits are almost always required before constructing all new wells and the repair, modification, and abandonment of an existing well, regardless of its size. Each state or locality has specific permits that you’ll need to acquire before the well construction can begin. So, do your research and ensure you have all of them. Typically, contractors won’t begin construction without all the necessary permits.
· Estimate the Amount of Water Your Household Will Need
Every household uses different amounts of water, so there’s no one-size-fits-all for well pumps and the amount of water they can comfortably deliver within a specific time. Estimating your household’s water usage will make it easier to determine the type of set you’ll need. To provide some context, the average American family uses more than 300 gallons of water per day. Because well pumps vary in efficiency, calculating the average amount of water your household will use can help determine the best type of well pump and pressure tank for your well system.
How to Maintain a Well System
Proper well system maintenance is crucial to ensuring a safe and reliable water source and preventing costly and inconvenient breakdowns. Well owners should keep a log that contains the details of their water well system, including the depth of the well, current water level, and equipment information. These details will come in handy if a contractor needs to respond to a service call.
We recommend an annual well maintenance check and a bacterial test to keep the well system performing at its best. The annual checkup should involve a visual inspection of the wellhead, the well system components, and other equipment to discover issues that could affect water quality. The water should also be inspected if there is a change in taste, smell, and appearance.
You may need to clean the well if the water is cloudy or contaminated with any suspended matter or if the water has developed an odor or taste problem. A positive test for biological activity or a decrease in the well’s capacity will also require the well to be cleaned.
Here are a few practical tips to help you maintain your well system safely:
- Regularly inspect the well cover or well cap to ensure it’s in good condition.
- Practice preventive maintenance to reduce maintenance costs in the long term.
- Consult qualified well system contractors to service your well. Do not try it on your own.
- Keep toxic chemicals, such as motor oil, pesticides, and fertilizers, away from the well site.
- Ensure there’s adequate distance between your well, waste systems, and chemical storage locations.
Well Water Contamination
Well water contains high quantities of healthy minerals, such as calcium, magnesium, and sodium. However, a well can be easily contaminated if it is not constructed correctly or toxic pollutants leach into it.
Harmful materials spilled or dumped near a well site can enter the aquifer and contaminate the groundwater drawn from that well. Whenever it rains or when large amounts of snow or ice melt, the water can pick up any loose liquids and contaminants it passes along the way and wash them down into aquifers containing large groundwater deposits.
Some popular sources of these contaminants include:
- Natural sources: Some substances found naturally in rocks and soils, such as arsenic, iron, chlorides, sulfates, fluoride, or radionuclides, can dissolve in groundwater. Other naturally-occurring substances, such as decaying organic matter, can move in groundwater as particles. Some of these contaminants may accumulate in excess quantities, posing a health threat if consumed. Others may produce an unpleasant odor, taste, or color. Groundwater containing these materials needs to be treated before it is used for domestic uses.
- Waste from sewers: Sewer pipes carrying wastes sometimes leak fluids into the surrounding soil and groundwater. Sewage consists of organic matter, heavy metals, inorganic salts, bacteria, viruses, and nitrogen. Similarly, improperly designed, located, constructed, or maintained septic systems could leak bacteria, viruses, household chemicals, and other contaminants into the groundwater, causing severe problems. Pipelines carrying industrial chemicals and oil-brine have also been known to leak, especially when the materials transported through the pipes are corrosive.
- Landfills: Landfills are areas where our garbage is taken to be buried. They are supposed to have a protective bottom layer to prevent contaminants from leaching into groundwater. However, if there’s no layer or the layer is cracked, contaminants from the landfill (paint, acid, car batteries, household cleaners, etc.) can make their way down into groundwater. These contaminants can pose serious health risks to humans and animals.
- Saltwater: When aquifers near the coast are over-pumped, there’s a risk of creating a vacuum that can quickly be filled with salty seawater. Saltwater is undrinkable and unsuitable for irrigation, decreasing the availability of the already scarce freshwater. Saltwater contamination is a significant concern for many coastal communities that depend on wells for drinking water.
- Improper disposal of hazardous waste: Many of us don’t realize that the way we dispose of waste can impact the quality of the same groundwater we use. When we improperly dispose of materials such as cooking and motor oils, lawn and garden chemicals, paints and paint thinners, medicines, disinfectants, etc., they usually end up in groundwater wells. Besides, many substances used in the industrial process should not be disposed of in drains at the workplace because they could contaminate a drinking water source. Pouring the wrong chemicals down the drain or neglecting to discard medication properly can harm your groundwater sources and, ultimately, your health and possibly that of the people living in your household.
- Mining and quarrying: Mining and quarrying can release pollutants previously trapped in rocks into surrounding underground water sources. Precipitation causes these soluble chemicals to leach into the groundwater below. These wastes often include acid, iron, sulfates, and aluminum. Furthermore, toxins such as lead and arsenic were used in 19th-century mining and often persist in today’s abandoned mine-shafts.
Contaminated wells used to obtain drinking water are especially dangerous. Drinking contaminated groundwater can have severe health effects. Dangerous illnesses, such as cholera, dysentery, and hepatitis, may be caused by contamination from septic tank waste. Poisoning may occur from toxins that have leached into well water supplies. Often, the contaminants that cause these illnesses go unnoticed for long periods while silently affecting large communities. When congenital disabilities, various types of cancers, and other symptoms appear, the effects of contaminated groundwater are reported. Poor water quality can also harm any industry linked to groundwater use. For example, anglers suffer when their catch becomes infected with various chemicals released into groundwater or when it dies prematurely as a result.
How to Keep Contaminants Out of Your Well Water
If your water comes from a private well, you are solely responsible for ensuring its quality. That’s because the United States Environmental Protection Agency (EPA) doesn’t monitor or regulate private wells, nor does it provide recommended criteria or standards for them.
The most reliable way to tackle potential contaminants in your well water is to install a water filtration system. Even if your well water isn’t polluted, it’s always better to prepare for the unknown. Generally, water filtration systems are designed to eliminate various hazardous pollutants from water, including heavy metals, pesticides, organic and inorganic waste materials, microbes, and many more.
If you decide to go this route (which we highly recommend), your best filtration option is either a whole-house filtration system or reverse osmosis (RO) filter. The Springwell WS1 Whole-House Well Water System is the perfect solution for private wells.
The Springwell WS1 Whole-House Well Water System
The WS1 uses the latest and most innovative water filtration technologies to efficiently remove iron (known for causing orange hair), pesticides, sulfur (causes rotten egg odor), and manganese, all of which are contaminants often found in well water. Plus, it’s more economical and environmentally-friendly than most other well water filtering systems on the market.
When paired with a sediment filter, one of our salt-based or salt-free softeners, and our powerful UV water purification system, you can ensure a more thorough filtration process.
- The sediment filter removes dust, sand, debris, dirt, and other suspended particulate matter potentially in your water.
- The softener combos help remove hardness minerals from your water that would otherwise irritate your skin and hair and destroy your laundry, water-using appliances, pipes, and plumbing fixtures. You can choose between the salt-based model and the salt-free model, depending on your situation.
- The UV Water Purification System add-on targets and destroys 99.9% of bacteria, cysts, viruses, parasites, and other microbes common in well water.
But if you are looking for a smaller, more compact unit that only treats water at specific taps in your home, a reverse osmosis system would be ideal.
The Springwell SWRO Under-Counter Reverse Osmosis Systems
Reverse osmosis is one of the most effective water treatment methods for eliminating well water contaminants. Our Springwell SWRO under-counter reverse osmosis systems are robust, efficient, and highly affordable point-of-use RO systems designed to remove all kinds of contaminants from well water. Their four-stage filtering process eliminates pollutants such as sediments, arsenic, nitrates, pesticides, lead, iron, sulfur, fluoride, etc.
Both systems come with a practical, easy-to-read instruction manual to walk you through the installation process. Plus, you can use our DIY installation video as a guide if you choose to get your hands dirty. We offer a lifetime warranty on all systems, a six-month money-back guarantee, free shipping, over 50 percent in factory-direct savings, and excellent financing options.
Contact us today to learn more about how each of these high-performance units can help protect your well system and keep you and your family safe. We’ll be more than happy to help you find the system that best suits your budget and needs.
Wells are a worthwhile investment for many homeowners, especially those living in rural and remote communities. These systems have come a long way from ancient history. They are still being used today – with newer plumbing technology and increased efficiency – to provide a reliable supply of healthy mineralized water for consumption. While setting up a well system these days can be costly, time-consuming, and will require much inquiry on the owner’s part, the long-term benefits of well ownership are undeniable. As long as you know the components of a standard well system and how they work together to supply water to a home, it becomes much easier to maintain your well system. But always remember that because wells are susceptible to contamination, you’ll need to take steps to keep out potentially harmful pollutants. Oh wait, we’ve already provided some effective methods to keep you and your family safe.