A Brief History of the Pop-Up Sprinkler
From a patent in 1933 to the MP Rotator, the story of how the pop-up sprinkler evolved — and why every step forward was slower than you'd think.
The first one was not really a pop-up
The first sprinkler head that would look recognizable to a modern irrigation contractor was patented in 1933 by Orton Englehardt, a citrus farmer in Glendora, California. He wanted a way to water his orange grove without having to walk out and move hoses every few hours, and he wanted the heads to disappear into the ground when they were not running so he could drive his tractor over them.
What he came up with was a brass fitting that used water pressure to push a rotating arm above the surface of the ground. When you turned the water off, the arm dropped back down into a small cylinder. It was closer to a golf course rotor than a modern pop-up spray head, but the idea was there: a head you didn't have to move, that disappeared when it wasn't running.
He sold the patent to Glenn Thompson in 1935, who turned it into a company called Rain Bird Manufacturing. That company is still around today. They changed their name slightly. You have probably installed a few thousand of their heads.
The gear-drive revolution
For the next thirty years, pop-up heads were almost all impact heads. The classic Rain Bird with the arm that goes click-click-click as it spins — that design ran commercial and residential irrigation from the 1930s until the late 1970s. It was reliable, simple, and the only way to get good coverage over a large radius.
Impact heads have two problems. They are loud. And they have mechanical parts that wear out. If you have ever had to replace the spring on an impact arm, you know what I am talking about — it is one of those jobs where the part costs $3 and the labor costs $30.
In 1981, James Hunter (yes, that Hunter — the company is named after him) introduced the gear-driven rotor. Instead of an arm smacking a stream of water to redirect it, a gear train inside the head slowly rotated the nozzle. No noise. No impact. No wearing spring. Just a sealed mechanism that would keep rotating for years.
The first one was the Hunter I-20. It is still in production today, 45 years later, more or less unchanged in its core design. You can still buy replacement parts for a 1981 I-20 that will fit a 2026 I-20. Very few products in any industry have that kind of continuity.
The spray head arrives
Pop-up spray heads — the short ones with the fixed-pattern nozzles that you use in residential turf — came along around the same time the gear rotors did. The early designs were not great. The plastic was brittle. The seals failed constantly. And the nozzles were not matched for precipitation rate, which meant you could put six different spray heads on the same zone and end up with some areas getting twice as much water as others.
This last problem is the one that took the longest to solve. For decades, "matched precipitation rate" was a nice idea that nobody actually implemented. You just picked nozzles that had the same radius and hoped for the best.
The fix came from an unlikely direction. In 2005, Hunter released the MP Rotator — a replacement nozzle that threaded onto a standard spray head body, but instead of spraying a fixed pattern, it used a rotating stream. The stream moved slowly, the water droplets were larger, and — critically — the precipitation rate was the same across every nozzle in the product line. You could mix full-circle, half-circle, and quarter-circle MP Rotators on the same zone and actually get matched coverage.
The MP Rotator was not the first product to try this. But it was the first one that worked well enough that contractors started using it by default. Twenty years later it is still the benchmark for residential irrigation coverage.
What we have and what we don't
Here is the thing about sprinkler head history: the big jumps happened decades apart. Impact to gear-drive took about 45 years. Gear-drive to MP Rotator took another 25. And the period in between each jump was not flat — it was full of incremental improvements that added up. But the big step changes are rare, and they are driven by material science and manufacturing precision, not marketing.
What is coming next is probably something around smart nozzles that can change their flow rate on the fly — reducing precipitation during hot weather, increasing it for saturation tests, reporting their status back to a controller. Rain Bird and Hunter are both working on this. Neither of them has something that works well enough to ship in volume. Give it ten years.
In the meantime, the humble pop-up spray head is still doing 90% of the work in residential irrigation. It has been doing that for forty years. And the parts that fail on a 2026 spray head are mostly the same parts that failed on a 1985 spray head — seals, springs, wipers, and the nozzle itself.
The tools get better. The fundamentals stay the same.
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Sources: Wikipedia articles on Rain Bird, Hunter Industries, and irrigation sprinklers (CC BY-SA 4.0). US Patent 1,925,018 (Englehardt, 1933) is public domain. The MP Rotator introduction date is documented in Hunter Industries press materials (2005).