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Recent Changes in Above-Ground Pasture Pipe Requires Matching Pipe and Fittings Correctly

Updated March 04, 2019

Pete Bauman

SDSU Extension Natural Resources and Wildlife Field Specialist

Above Ground Pipe Systems

Above ground water systems have become a very popular tool to deliver clean water from reliable sources to pastures across South Dakota. Recently, there have been some changes in manufacturing and suppliers that are worthy of note as producers and suppliers design systems. We wanted to share an example of a recent above ground pasture pipe installation project SDSU Extension assisted with.

Typically, these systems are relatively easy to put together. However, on this project getting the fittings to fit well was a struggle, requiring tapering the pipe ends and a liberal application of soapy water to reduce friction between the pipe and the O-rings in the compression fittings. Even with these preparations, the installation was difficult and still required two men to push the fittings together; obviously, something wasn’t right.

System Anatomy

Pipe Type

Above ground pipe systems have in general a few things in common. The type of pipe used in these systems is not the common black pipe found at home improvement stores. Flexible above ground pasture pipe is made of high-density polyethylene (HDPE) and is usually rated at 160 psi. This is a very tough material that can withstand being driven over by lighter vehicles. Some producers even allow water to freeze in these pipes (although this isn’t necessarily recommended). Pipe size can vary depending on application, with 1”, 1 ¼”, 1 ½” and 2” pipe being popular in our region.


Above ground systems also offer many components including T’s, elbows, valves, drain ports, and other compression fittings with large threaded collars that are designed to be installed by hand, allowing for quick coupling and decoupling of components. Compression fittings are generally rated at 200 psi.

an above ground pipe installation

Installation Considerations

The difficulty putting this system together in the above example was uncommon. A couple of distributors and installers were contacted by SDSU Extension, and the questions we had prompted some investigation on their part. One individual contacted was Rick Smith, owner of PastureWorks out of Hayti, SD. Rick has worked with many producers on custom systems and we were curious if he was having any issues with any of his recent customers. He had not, but he did acknowledge that some of these new fittings were more difficult to install than the older ones. We discussed some possibilities for the problems and Rick agreed to do some fact checking on these issues.

Pipe Selection

After his inquiries, Smith cautions that producers and installers should pay attention to the type of pipe they purchase, and should design their systems components accordingly. The pipe can either be manufactured to inside or outside diameter tolerances. Both can work, but it is important to know what type of pipe has been ordered so that the correct couplers are purchased to match the pipe. Pipe, manufactured based on inside diameter tolerances can have some variations in outside diameter, and thus the correct couplers should be used to avoid difficulty in installation. Unfortunately, in the example above, the supplier provided pipe that was an inside-tolerance pipe, whereas the compression fittings were based on outside tolerance. Therefore, the slight variations in thickness of the pipe wall affected the outer pipe diameter, resulting in many of the fittings being very difficult to install.

Purchase Considerations

Price differentials for inside vs. outside tolerance pipes can be significant as can that of inside vs. outside tolerance compression fittings. So, a word of caution, ask these questions of your supplier before you make the purchase. Many of us have assumed some of the new fittings on the market from different manufacturers are universal, but it turns out they are not!

Related Topics

Conservation, Pasture, Range