Understanding inches per hour is the essential measure for sprinkler precipitation in landscape irrigation, especially in Nevada’s desert climate.

Water, water everywhere—but how much of it actually lands where you want it? In the world of landscape irrigation, one number matters more than slick flow rates or fancy nozzle names: the precipitation rate. And for Nevada landscapes, that little metric can spell the difference between lush, healthy plants and a thirsty, wasted patch of ground.

What is precipitation rate, anyway?

Let me explain in plain terms. Precipitation rate is the depth of water that lands on a specific area in one hour. The unit is inches per hour. So, if your sprinkler zone covers a 20-by-20-foot patch and your sprinklers deliver water at a rate of 1 inch per hour, you’d expect about 1 inch of water to soak into that patch over 60 minutes. That number—1 inch per hour—becomes a guiding line for how long you should run that zone, what soil can soak up, and how much water plants actually receive.

Why inches per hour instead of gallons per minute?

Here’s the thing: gallons per minute is a flow rate, not a measure of how much area gets water or how quickly soil can absorb it. You might have a high gallons-per-minute flow, but if the water lands on a slope or sandy soil and runs off or drains away before infiltrating, you’re wasting water. Inches per hour ties the water delivery to the landscape itself—the soil’s ability to absorb and the plant’s needs over a given area. It helps you answer practical questions: Is this zone applying too much for a clay soil? Does a sandy area need a longer run time to reach the same depth? Is the system delivering evenly across the whole zone?

A quick mental model

Think of your irrigation system as a garden-hose sprinkler with an on-board calculator. If you run a zone for 30 minutes and the average catch depth you measure across the zone is 0.5 inches, the precipitation rate is 1 inch per hour. That’s because 0.5 inches in 30 minutes scales up to 1 inch in 60 minutes. Simple math, big payoff in accuracy.

How to measure it in the field (without turning irrigation into a mystery)

You don’t need fancy gear to know the precipitation rate. The classic catch-can test keeps it honest and repeatable. Here’s a straight-forward way to do it:

• Pick several small catch containers. You can use the old tuna cans or small plastic cups—anything with a uniform opening that won’t evaporate water quickly. Place them evenly across the zone you’re testing. You want to cover the same area that the sprinkler head set is designed to water.

• Run the zone for a fixed period. Common durations are 10, 15, or 20 minutes. Keep it consistent for each test.

• Collect and measure. After the run, measure the depth of water in each can with a ruler. If some cans have more water than others, you’ll want to average the depths to get a single representative number.

• Convert to inches per hour. Add up the inches from all cans and divide by how many you measured to get the average depth in inches. Then scale to an hour: multiply that average by 60 divided by the test duration in minutes. For example, if your average depth is 0.25 inches and you ran for 15 minutes, the math is 0.25 × (60/15) = 1.0 inches per hour.

Pro tip: keep it simple, but be thorough. The more cans you use (spread across the zone, including edges and any slope), the more accurate your rate will be. And if the depth varies a lot, you might split the zone into sub-zones and test each one.

How to use the number in real projects

Once you know the precipitation rate, you turn it into decisions. Here are a few ways it shows up on the job:

• Scheduling run times. If your zone’s target water need is, say, 1 inch per week and the zone can apply at 1 inch per hour, you’d run it for about one hour per week (adjusted for rainfall, evapotranspiration, and weather). If the rate is 2 inches per hour, you’d run it for half an hour and spread that water across two sessions to keep soil from becoming waterlogged.

• Avoiding runoff. Slopes or heavy clay soils can push water to run off before it soaks in. By knowing the rate, you can under-run a bit and then repeat the cycle, giving the soil time to absorb water gradually.

• Plant health and soil type. Different plants and soils drink at different paces. A sandy bed will take up water quickly, while heavy clay holds onto moisture longer. Matching precipitation rate to soil infiltration keeps roots happy and reduces waste.

• Water regulations and budgets. In regions with strict water rules, keeping irrigation within a sensible rate helps you stay compliant and conserve resources.

A quick example to bring this home

Suppose you’re designing—or retrofitting—a small lawn plus shrubs in a Nevada yard. You test a sprinkler zone and find an average depth of 0.4 inches in 15 minutes. The precipitation rate is 0.4 × (60/15) = 1.6 inches per hour. That means, if you want to apply about 1 inch of water for a typical weekly irrigation window, you’d schedule roughly 0.6 hours (36 minutes) of watering per week for that zone, adjusted for weather and evapotranspiration. If the zone covers a stony slope, you might break that into two shorter runs to reduce runoff. Easy to manage once you know the rate, right?

Why this matters in the real world, especially here

Nevada landscapes contend with heat, wind, and diverse soils. In many parts of the state, the ground can bake dry between storms, and the air can whisk away moisture fast. That reality makes a precise precipitation rate not just handy but essential. It helps you dial in the right amount of water, minutes at a time, instead of blasting water for hours and hoping for the best.

Let me pause for a moment to connect this to common-sense design choices. If you’re planting drought-tolerant shrubs, you may push toward lower annual water needs. If you’re preserving turf on a hot day, you’ll want to make sure water isn’t pooling after a minute or two because the soil is soaking in fast or slow. The precipitation rate becomes your compass in those choices. It also acts as a practical check against overwatering, which can lead to root rot, nutrient leaching, and higher water bills—none of which are appealing on any street, but especially in arid environments.

Common missteps to watch for

No system is perfect on day one, and even experienced crews slip up here and there. A few pitfalls to avoid:

• Assuming gallons per minute tells the whole story. If you don’t translate flow into area-based depth, you’ll over-water some zones and under-water others.

• Running tests for too short a time. Short tests can skew the average depth, especially if the spray pattern is uneven.

• Forgetting to account for wind. A light breeze can skew measurements by whisking away some water before it lands in the cans.

• Neglecting to check uniformity. A single bad head can ruin an entire zone’s rate if it’s not identified and corrected.

• Ignoring soil type. Infiltration rates vary; a rate that makes sense on sand may overwhelm clay.

Tools of the trade—what you actually need to measure

• Catch cans or any uniform containers

• A ruler or measuring tape

• A stopwatch or timer

• A pencil and simple log to record depths and times

• A map or layout of zones so you can test multiple areas

• A note of soil type and slope, if you’re mapping larger zones

Keep it simple, then expand as needed. If you’re in Nevada, you might pair this with a quick look at ET data for the season and a glance at local watering restrictions. Those small steps help you align irrigation with real plant needs and local rules.

A practical, bite-sized checklist you can use

• Identify one zone to test, preferably representative of the area (shade vs sun, slope vs flat).

• Place 5–7 catch cans evenly across the zone (more is better if you’ve got the time).

• Run the zone for 10–20 minutes, depending on your setup.

• Measure water depths in each can; compute the average.

• Calculate precipitation rate: average depth × (60 ÷ test minutes).

• Compare the rate to your target water needs and soil infiltration rate.

• Adjust run time or schedule, then re-test to confirm the change.

A few closing thoughts

Water is both a resource and a responsibility. The precipitation rate is the practical bridge between what your system delivers and what the landscape actually uses. It’s not just about hitting a number—it’s about turning that number into better plant health, steadier soil moisture, and wiser water use. When you measure inches per hour, you’re not merely ticking a box on a checklist; you’re shaping a landscape that thrives with less waste, even under Nevada’s blazing sun and gusty afternoons.

If you’re curious, you can apply this approach to any zone—sunny or shady, sandy or clayey, flat or sloped. The math stays the same; the implications grow with every test you run and every tweak you implement. And if you ever feel overwhelmed by the different nozzle patterns, heads, and zones, remember this: the precipitation rate is your common language. It translates the mechanics of your sprinkler system into real, observable outcomes on the ground.

So next time you review an irrigation plan, keep your eye on that rate. Inches per hour isn’t merely a unit; it’s the practical guidepost that helps you design, schedule, and manage irrigation with confidence. It’s a straightforward metric, but its impact is anything but small. With a little patience and a quick test, you’ll be speaking the language of efficient, plant-friendly watering—and you’ll see the difference in the yard you’re building, one precise inch at a time.