Why is the drop pipe hole offset in my ABS well seal?

From time to time there are questions regarding the drop pipe offset, with the concern being raised that the offset will cause issues with the pump installation down the well. In theory the concern appears to have merit, however it is of NO concern in reality - this is a myth.

First of all, one should be aware that the use of offset drop pipes is very common by all manufacturers. Offset drop pipes are necessary on smaller diameter seals with larger drop pipes to allow the seal to be designed with proper vent and wire cable holes and bolt patterns that do not interfere with the drop pipe coupling or tee installed at the well head. These seals are installed on large pump installations every day without any issue. However, when a smaller drop pipe (1" or 1-1/4") is offset on smaller installations some will question whether the offset will cause problems. The fact of the matter is that wells are very rarely drilled "plumb" or in "perfect alignment" therefore the offset in the drop pipe will NEVER cause a problem with submersible pump installations!

NOTE: A well is within tolerance when it is off vertical by 1.2" in 100' (may vary depending on the jurisdiction). Therefore it could be argued that in the majority of installations the offset is a benefit allowing the installer to rotate the seal to compensate for the wells out-of-alignment issues and better center the pump in the well. The bottom line is that it simply is a non-issue.