What Are the Parts of a Well Water System?

Posted by
John Woodard on September 29, 2023

According to the United States Geological Survey, about 15 percent of Americans use well water in their home. In each of these homes, a well water system provides clean water at the convenience of the turn of a faucet. A faulty or insufficient well system can lead to unsafe, unavailable, or slow water flowing from the faucets and fixtures. For homeowners new to well water systems, the components of a well may seem overwhelming. However, wells use fairly few parts that communicate with each other to provide a home with water. In this article, you can discover the major components of a well water system and how they work together to provide a home with clean water.

Components of a well water system

A home well water system is composed of six major parts: a well casing, well cap, water pump, pressure switch, pressure tank, and water filtration systems. These systems work together to deliver well water to a home as water safe for drinking, cooking, bathing, and other uses as needed.

Well casing

A well casing is a tube that prevents the well’s access opening from collapsing. It is also sealed off to prevent outside contaminants from entering your water supply. A well casing may be made of carbon steel, stainless steel, plastic, or concrete. It allows the pump to maintain access to the water supply while also protecting the well from foreign objects.

Well cap

A well cap, as the name suggests, is a lid that sits on the well casing. It shields a well water supply from debris, organic matter, pathogens, and runoff. Well caps can be made from either aluminum or plastic, and they incorporate a vent to equalize the pressure on the interior and exterior of the casing.

Well pump

A well pump delivers water from the well itself to the pressure tank. Depending on the type of pump used, it can be installed above the well or submerged in it. Well pumps above the waterline use suction to provide the system with water, while submersible pumps push water through a pipe to reach the tank. The size of a well ultimately determines which type of pump is best for a specific well water system. For example, jet and centrifugal pumps only function in shallow wells, while submersible pumps can be used in practically any well type.

A well pump, pressure switch, and pressure tank all coordinate to provide a home with water. The pressure switch tells the pump when to turn on, and the pressure tank communicates the tank's pressure with the pressure switch, allowing the switch to signal the pump. These communications allow the system to run efficiently with low power usage and increased longevity.

Learn more: What is a well pump and how does it work?

Well pressure switch

A well pressure switch detects pressure from the pressure tank to signal the pump when needed. The main purpose of a pressure switch is to preserve the life of the pump by helping it run efficiently. During usage, water flows from the tank, causing pressure to drop until it reaches the preset level. Once this threshold is reached, the pressure switch signals the pump to turn on. The pump will run until the tank fills to a maximum pressure threshold. At this point, the pressure switch tells the pump to power off. This cycle enables the pump to run uninterrupted for a calculated period of time to keep the pump cool rather than every time water is needed in the home. A properly functioning pressure switch greatly increases the lifespan of a well pump.

Learn more: What is a well pressure switch and how does it work?

Well pressure tank

The well pressure tank stores water until a water fixture in the house is opened. These tanks contain a pressurized bladder that maintains pressure as water fills and empties from it. Once a tank reaches the maximum capacity it can hold while maintaining pressure, called the "drawdown", the pressure will reach a cut-off point that will tell the pressure switch to turn the pump off. Once the tank empties to a preset point, the pressure switch will detect the pressure change and signal the pump to fill the tank again. As a result, the size of a home's pressure tank should have enough drawdown volume to allow the pump to stay cool and not overheat due to start and stop cycles.

Learn more: How to size a well pressure tank

A well pressure tank adds pressure to the water inside. In well systems where water pressure is too low to pass through various filtration systems, homeowners may wish to install their pressure tank upstream of the filters. Note that in this configuration, the lifespan of the tank’s bladder and other components may be shortened by the sediment, minerals, or other contaminants in the untreated water.

Learn more: Well pressure tank problems and how to fix them | How to check your well tank’s pressure

Water filters and treatment systems

The water filters and treatment systems in your well water system make water clear, delicious, and safe. Whole-house water filtration systems treat all water that enters a home from a well, while point-of-use filter systems provide extra filtration for specific faucets, such as the kitchen sink. Well water requires at a minimum some form of disinfection and sediment filtration. The most common water treatment systems in a well water system include UV disinfection systems, sediment filters, activated carbon filters, and reverse osmosis systems.

Well water disinfection

The most common form of disinfection for well water is UV water disinfection. UV water purifiers subject water to UV light as it flows through the system. The frequency of UV light in these systems is at a germicidal wavelength that deactivates microorganisms after a short time of exposure. To ensure the UV light effectively deactivates microorganisms, a sediment filter must be installed between the water source and the UV system. If sediment makes its way into a UV water purifier, it can block the UV light from reaching all water that flows through, leaving bacteria, viruses, and parasites active and capable of reproducing.

Additional well water treatment

Based on the contaminants present in well water, additional filtration systems may be needed. Reverse osmosis systems are a common filtration solution for those who want additional contaminant removal for their kitchen sink. These systems remove practically all contaminants from water apart from bacteria that has already been deactivated by a UV purifier. Other under-sink filters include KDF filters, activated carbon filters, and ultrafiltration systems.

Learn more: What is reverse osmosis? | 5 of the best under-sink water filters

Some wells may contain the water-hardening minerals calcium and magnesium. If present, these minerals must be removed by a water softener. Water softeners use brine to exchange magnesium and calcium ions with sodium or potassium ions, removing hardness from water. Water conditioners, also known as salt-free water softeners, should never be used on well water because they become ineffective when exposed to trace amounts of iron or manganese.

Learn more: Water conditioners vs water softeners

How to choose a well water filtration system

Ultimately, the type of water filtration you choose for your well is determined by the contaminants in your well water. If you are new to owning well water or are searching for a more thorough filtration system, begin by testing your well water. For comprehensive testing, consult a laboratory listed on the EPA’s certified laboratory list. This contains quality laboratories in each state, allowing homeowners from all across the country to test their well water quickly.

Learn more: What is the best type of filtration for well water?


If you have any additional questions, please do not hesitate to contact us.

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