Pitless Adapters: What They Are & What They Do

pitless-adapters

Unlike modern wells, in the early days wells commonly had a well pit and wellhead or union fitting that would connect the drop pipe to the supply fitting. The purpose of a well pit is to prevent water supply lines from freezing in regions with a colder climate, with an added advantage of allowing easy access to the technician for routine maintenance.

However, when covered with an access cover, these pits can deteriorate over time and become a trap for animals or small children. A tight-fitting access cover can also trap underground gases, making it a dangerous place to work. It is also possible that the concrete wall casing of the well pit can start cracking and disintegrating eventually, allowing surface water to seep into the pit and consequently contaminate it. 

Enter pitless adapters; a simple, elegant solution that makes the aforementioned issues obsolete. These adapters eliminate the need for a well pit, hence the term “pitless.”

How Pitless Adapters Work

Pitless adapters provide a water-tight connection between the drop pipe from the submersible pump inside the well and the water line running to the service location. The device not only prevents water from freezing but also permits easy maintenance of the well components without the need to dig around the well. The adapter comes in two pieces that can easily slide together to create a water-tight seal.

A fundamental difference of the pitless adapter from the conventional wellhead is that the drop pipe exits from the side of the casing rather than from the top. Such a change is possible because the connection of the two pipes is at a 90-degree angle. Also, the adapter is kept below the frost line to prevent the water from freezing. 

The Benefits of Pitless Adapters

The 90-degree bend in the flow of water allows for the wellhead to be extended above the ground. As a result, the chances of surface water contamination reduces considerably. Extending the wellhead above ground also allows easy access for well maintenance.

The design of the pitless adapter also facilitates easy maintenance and component removal. For example, if you need to remove the internal assembly of the well, you can simply screw a tool to the threaded male component of the pitless adapter and pull the assembly out.

In addition, it is also easier to perform other maintenance tasks such as well chlorination or video well inspections when compared to working on an underground wellhead.

Types of Pitless Adapters

There are two popular types of pitless adapters differentiated based on their operation and connection mechanism.

Slide Pitless Adapter

Slide pitless adapters are more common in residential and commercial applications. You can install these adapters by making a hole through the well casing. Slide pitless adapters can connect with pipes of up to 2" diameter. Both the male and female components of the adapter consist of gaskets and single O-rings. These sealings create a water-tight joint, both inside and outside the well casing, to prevent leakage. 

Apart from their typical applications in submersible pumps, pitless adapters are also sometimes used to install the riser pipe and foot valve in shallow well jet pump systems.

Spool Pitless Adapter

A spool pitless adapter is made up of two key components: the spool and the discharge housing. The spool adapter is housed in between the upper barrel and the well casing. Typically, this discharge housing or the upper barrel is 2” larger in size than the well casing. The well is then sealed off with a well cap. 

While a slide adapter creates a compression seal by sliding the mating parts into place, a spool adapter creates a compression seal between the circumference of the spool and seats in the discharge housing using two O-rings. 

You can simply pull out the submersible pump for maintenance or emergency repairs by lifting the spool and pipe columns using a lift-out assembly.


Pitless adapters have eliminated the need to have dangerous and unsanitary well pits. In addition, these adapters provide a quick and easy connection below the frost line and make well maintenance more convenient. Slide and spool pitless are two common types of pitless adapters that are essential in moving water from the source to the desired service location. Although both these adapters have a common purpose, their applications differ mainly due to their difference in design.

If you’re looking for a pitless adapter or any custom pump parts, Hayes Pump can help. With our partnership with ProCast, we deliver custom manufactured parts that meet your requirements and keep your pumps running optimally.

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