Water Well 4 Step Selection Guide for Well Seals

When selecting a well seal that best fits your application, there are multiple factors that need to be considered. Do you require single hole or a double hole design? Should you get cast iron or ABS? Every application differs in what requirements the well seal needs to have, making it a difficult task to guarantee you are selecting the right one.

In this blog, we will provide you with all the tools to ensure you select the proper well seal for your operation, leaving you and your team happy and stress free. Let's get started!

For a detailed run down about what exactly a well seal is, check out our blog What is a Well Seal?


Selection Steps

1. Figure Out Well Casing Size

Before purchasing your well seal, you need to determine the size you require. The most important thing to remember is that the well seal fits inside the well casing, meaning your measurement should be the inside diameter (I.D) of the casing. The measurement needs to be made very carefully because in this case, close does not cut it.

2. Determine the Number of Drop Pipes you Require

There are typically 3 options for drop pipe holes; blank, single hole and double hole. Let's take a closer look at each.

WS40 (top)

Blank: Having a blank well seal means there is no pipe needing to go down the well. This well seal is used for capping a well or could also be used as a well cap if the submersible pump is on a pitless. This application is very uncommon.

WSP4012Single Hole: A single hole well seal means there is only one pipe needing to go down the well. This well seal is generally used for installing either a shallow well jet pump or a submersible pump. There are two tappings included on this style of well seal, one is a vent tapping and one is a cable hole tapping for submersible pump installations.

Double Hole: A double hole well seal is designed to allow two pipes to go down the well for a deep well jet pump installation. The large hole is for the larger drop pipe that takes the water to the surface and the other hole is for the smaller drop pipe that sends a smaller volume of water down the well. This allows the jet pump to suck the water back up from a deeper well.

The difference between theWS601210 double hole and single hole is the double hole is equipped with one vent tapping only. There is no cable tapping as no wires go down the well on a jet pump installation.

3. Establish the Drop Pipe Size

Single Hole Seal

You need to determine the nominal IPS pipe size for the drop pipe, sometimes known as the riser pipe. This pipe will transfer the water from the well up to the surface. Generally, this will be about 1" or 2" for typical submersible pump applications that range from 4" to 6" well casings. For wells 7" up to 12", the drop pipe sizes may be as large as 6".

Double Hole Seal

For this measurement, you will need the nominal IPS pipe size for the "Drive" or pressure pipe. This pipe circulates the water from the pump and takes it down the well through the ejector nozzle and venturi tube into the riser pipe. Eventually, this will take the water to the surface.

4. Verify the Material

The three materials that well seals are commonly found in is Cast Iron, ABS and Steel. You may run across from time to time a well seal that is made from stainless steel, depending on what the application requires. If you want to learn about split vs solid plate designs for well seals check out this blog, What is a Well Seal?

Cast Iron

WS62 (top)Initially, all well seals were made from Cast Iron. They were relatively inexpensive and they could be made in different shapes and sizes. Cast Iron well seals are suitable for a majority of installations with pump sets up to 300' and they are available in split plate design. The downfall is they are susceptible to rust and cracking during installation. They also have a limited strength, they are not best suited for deep pipe sets greater than 300'.

ABS (Plastic)

ABS well seals have become much more economical compared to cast iron. They are also suitable for most installations and they do not rust or corrode improving their popularity. ABS well seals are WSP401210extremely cost effective and there is an option to add stainless steel hardware if your application calls for that. Another benefit is that they are available in both solid and split plate design making it likely that there is an ABS well seal that will work with your required application. Unfortunately, they are not suitable for deep pipe sets greater than 300'.


In areas where aquifers are deeper than 300' and pump sets could potentially be up to 1200', a steel well is the best option. They are formed from solid steel plates for exceptional structural strength. WSS6010They are typically available in sizes all the way up to 12" and are significantly stronger than cast iron or ABS. They are however, usually higher in cost and smaller sizes have thinner top plates compared to the cast iron and ABS well seals.

Stainless Steel

Stainless steel well seals obtain the same physical characteristics as the steel well seals but the stainless seals have the ultimate corrosion resistance. Just like the steel well seals, they are suitable for very deep pump sets up to 1200' and they are also available in solid and split plate design. Stainless well seals are the most expensive option and similar to the steel seals, the smaller sizes have a thinner top plate.


In a nut shell, different well seals are designed for a variety of applications. Knowledge is power and being informed about the different options will ensure you correctly select not only the perfect material but the exact size you require. Keep these steps handy to remind you to do your homework before making the final decision, it will save you some trouble later on.

Have further questions about this subject?


Head over to Boshart's Knowledge Base: technical product information, guidelines, and more.