DIY Water Hauling Trailer for Irrigation

These resourceful landowners built a system to harness water on their unplumbed property.

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by Ward M Thurman
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Owning a piece of Montana real estate has been our family’s dream for years. Finally, in 2020, we bought 11 acres of much-neglected pasture on which to build our dream home and hobby farm. The property came without irrigation rights, but what attracted us to it (besides the stunning views of the Bitterroot Range) was the presence of a small pond and seasonal surface water. With water being our most precious resource – and the idea that Montana is only three days from a drought, or so the saying goes – we recognized we’d need a water hauling trailer to help manage our property’s water and allow us to irrigate with a portable watering system.

After considering our situation, we determined we wanted something that could pump water from our pond, a tank, or an external source; move or pump water to various locations; refill a tank; drain water by gravity from a tank; water our newly planted fruit trees; and have enough flow to use for firefighting if necessary.

As a solution, we bargained for an old, well-rusted, single-axle trailer that was built by Montana cowboys. Then, with our son, we set about converting the trailer into a piece of resource management equipment, aka “the water trailer.”

Water Hauling Trailer Assembly

Close up view of the steel banding serving as the hold down straps for the water tank.

Because our property doesn’t have electricity yet, we knew we’d need an alternative way to power a water pump. We considered a 12-volt direct-current electric pump that could run off of a vehicle, but the pumping rate was too low for our needs. After shopping around the ranch supply and hardware stores, we settled on a gasoline-powered pump rated for about 50 gallons per minute.

Next, we had to rehabilitate the old trailer into something that could carry a water tank and related parts. I won’t go into all the details about the trailer reconstruction, but it was interesting to learn that the axle probably came from an early 1950s Chevrolet!

After we finished the trailer modifications, we moved on to the pumping system. The first thing we had to determine was what size tank the trailer could hold.

After years working as a process engineer, I’ve retained at least a little useful information. For example, I know that water weighs 8.34 pounds per gallon. A visit to our local ranch supply store netted us a rectangular 150-gallon water tank that holds 1,251 pounds of water. We figured the tank, water, pump, piping, and additional hardware would weigh about 1,600 pounds total. As it turns out, that’s quite close to the weight of a 1950s Chevrolet front end.

Another thing I’d learned over the years in the industrial world is that small gasoline engines have an annoying habit of vibrating while they run. Maybe not as bad as our diesel tractor engine, but enough to eventually shake the piping apart.

Initially, we’d planned to use galvanized steel piping throughout the water tank system, because it would stand up to the vibration, but cost and a lack of tools for working with steel directed us to PVC. While not as robust as steel, PVC is lighter, easier to work with, and a lot cheaper. The downside of PVC is its fragility, so we thought including short pieces of flexible hose on both the pump suction and the discharge might reduce the vibration. Eventually, we drew up a plan for the system (see illustration, above) and went to work.

The first step was positioning the tank on the trailer. We set it in the center of the trailer, slightly forward of the axle to ensure there was enough tongue weight for balance. Once the pump was mounted on a plate secured to the trailer tongue, we laid out all the piping and fit it between the tank’s bottom connection and the pump suction. We also strategically placed threaded fittings so the system could be partially disassembled to make repairs. Lastly, we built bracing from pieces of angle iron we found at a local hardware store to support the piping. We made some compromises to our plan as we installed the piping, so it didn’t turn out exactly as the illustration shows, but it’s close.

illustration of water pipes

Then came the challenge of how to securely fasten a tank holding more than a half-ton of water to the trailer. Fortunately, the tank was designed with molded paths for tie-down straps. I’m inherently cheap and like to reuse discarded items whenever practical, so I had the idea to use discarded steel banding as strapping, because it’s strong but somewhat flexible. It’s the same steel that lumberyards use to secure bunks of lumber, and a visit to our local lumberyard netted a few lengths of the 1-inch-wide banding. Fortunately, we’d replaced the trailer’s plywood deck with expanded metal, so creating bolt-through anchor points for the bands was simple.

Steel banding is hard and brittle, so we used a torch to anneal short sections at the ends to soften the steel. This allowed us to drill holes for connections and made the ends a bit more resistant to fatigue cracking. We completed the hold-downs with four hook-ended bolts, some aluminum angle sections for anchor points, rubber strips at the corners to protect the tank from the banding, and a pair of turnbuckles. After that, the water hauling trailer was ready to be tested.

Portable Watering System Success

During the first trial run on our land, we ran the tank too low for the pump to prime from the pond. Wow, that was a lesson! Fortunately, we had just enough water in a jug to re-prime the pump. In light of this discovery, we added a foot valve at the end of the suction hose that keeps the pump primed, preventing such annoyances in the future.

Now that we’ve had a full season under our belts, we’ve found that the water hauling trailer is one of the most useful pieces of equipment on our budding farm. It’s come in handy for many of the jobs we created it for, plus a few we hadn’t planned on. We also use it to mix and apply liquid fertilizer, wet post holes for soil compaction, wash off tree stumps so we can cut them out without ruining a chainsaw in the dirt and rocks, control weed burns, and operate sprinklers. Rarely does a workday go by that we don’t use the water trailer for one task or another, even if it’s simply to wash off our grubby hands! The investment of time and money was well-spent.

The water trailer with a good view of the pump and piping. It was being used to water our fruit trees.

Ward and Kammy Thurman make their home in the Bitterroot Valley of Montana. You can follow their adventures on YouTube at Sapphire Mountain Farm.

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  • Updated on Jun 12, 2022
  • Originally Published on Apr 8, 2022
Tagged with: irrigation, resource management, utility, water trailer