Water Well A Common Offset Well Seal Misconception Explained

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Misconceptions are everywhere. We make decisions based on rumours and myths that we hear in our lives every day. This makes it important to learn the facts before making any major decisions. A large misconception lies around offset well seals and we are here to help set the records straight.

In this blog, we will take you down a path that will hopefully squash a major misconception about well seals, giving you all the information to ensure you are making the right choice.

Unsure of what exactly a Well Seal is? Check out our blog What is a Well Seal? or if you need help selecting the best Well Seal for your application check out our blog a 4 Step Selection Guide for Well Seals.

Prefer watching videos over reading? Check out our video above. The video delves into the same topic as the blog post!


Common Misconception

Slight offset seals will not allow the submersible pump to be installed and or properly centered in the well casing.

Three Reasons the Above is Not True

  1.  Both plastic and steel drop pipes have an enormous amount of flex. When the pump is down the pipe, the slight offset does not cause any issues. It is more likely that the crook in the well would be much more of an issue.
  2. The way wells are drilled now a days is not the same as it used to be. Wells used to be drilled much more vertically and straight than they are now. The AWWA (American Water Works Association) Standard allows for a maximum drift of 2/3 the I.D of the well casing per 100 ft. So for example, a 6" well may be out 3" in 150ft.
  3. Offset Well seals have been used for quite a long time with no issues recorded. They have been tested several times by the water well Industry with no concerns coming to light.

Benefits of Offset Well Seals

WSP4012-11Offset well seals have a slightly off center hole to allow for larger pump cables, as you can see in the picture. By having the offset hole, it allows room for a larger hole, meaning large pump cables can fit down the hole with no issues of the pump cable not fitting correctly. This helps make the installation process stress and trouble free.

Another important benefit is that offset well seals have a large pump cable hole (conduit connection) for submersible pump installations when flat jacket pump cable is being used. The flat jacket pump cable requires a long, narrow slot through the rubber sealing grommet kit. If the hole in the well seal is reduced, the flat jacket wire would not fit. With an offset well seal, that is not a worry.

Centered Well Seals

A centered well seal has the vent and drop pipe hole located directly in the center of the well seal. Small well seals that also have large drop pipe sizes create a situation where the only option is to reduce the pump cable connection, since there is not enough room for everything to be in the center of the well seal. This would require the pump cable connection to potentially be as small as 1/2" FPT which makes the installation process extremely difficult. This would also reduce the vent size to 1/4" in some cases.

Pitless Adapters

An interesting fact is that major concerns are brought up about offset well seals but pitless adapters actually have more of a compelling offset at the wellhead, much more than you would find in the offset well seals. It is believed that the issues don't get raised about pitless adapters because you can not see the drop pipe connection position to the center of the well as much as you can with offset well seals. Just something interesting to keep in the back of your mind when deciding whether to go with an offset well seal or not.


In some cases, concerns that get brought up are actually untrue causing you to make an incorrect decision. By bringing to light the misconceptions, it could change your perspective and actually benefit you. Offset well seals have great advantages that will make installation stress free. If you aren't using offset well seals now, you may want to consider them the next time you need a well seal.

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