Using a Can Test to Measure Sprinkler Rate and Uniformity

Using a can test to measure sprinkler rate and uniformity.
Using a can test to measure sprinkler rate and uniformity.
Start by collecting 6 or more same-sized containers with straight sides. We are using 10 coffee cans in this example. You'll also need a ruler.
Start by collecting 6 or more same-sized containers with straight sides. We are using 10 coffee cans in this example. You’ll also need a ruler.

 

Next, place the cans at random locations around your lawn.
Next, place the cans at random locations around your lawn.

 

The cans must be in the fully upright position for good test results.
The cans must be in the fully upright position for good test results.

 

Next, run your sprinkler system for 15 minutes. If water starts to run off of your lawn, stop the cycle and let the water soak in before completing the 15-minutes run time.
Next, run your sprinkler system for 15 minutes. If water starts to run off of your lawn, stop the cycle and let the water soak in before completing the 15-minutes run time.

 

When the cycle has finished, observe the amount of water in each can. If your sprinkler uniformity is good, the water level will be about the same in each can. If the amount varies by 50% or more, you'll probably need to make major renovations to your system to improve uniformity. A lack of uniformity is one of the most common causes of brown spots in lawns.
When the cycle has finished, observe the amount of water in each can. If your sprinkler uniformity is good, the water level will be about the same in each can. If the amount varies by 50% or more, you’ll probably need to make major renovations to your system to improve uniformity. A lack of uniformity is one of the most common causes of brown spots in lawns.

 

Collect all 10 cans and pour the water into a single can to make it easier to measure. If it won't fit into a single can, use two cans.
Collect all 10 cans and pour the water into a single can to make it easier to measure. If it won’t fit into a single can, use two cans.

 

Use the ruler to measure the total height of water from the 10 cans. We measured 3 1/8 inches of water. If you used two cans, add the measurements together.
Use the ruler to measure the total height of water from the 10 cans. We measured 3 1/8 inches of water. If you used two cans, add the measurements together.

 

For the next step, you'll want a calculator. We used the one on our computer.
For the next step, you’ll want a calculator. We used the one on our computer.

 

We measured a height of 3 1/8 inches. 1/8 inch=0.125 inch, so we have a total of 3.125 inches of water.
We measured a height of 3 1/8 inches. 1/8 inch=0.125 inch, so we have a total of 3.125 inches of water.

 

Next, divide the total height of the water (3.125 inches) by the number of cans used (10) to determine the average height of water in each can (0.3125 inches).
Next, divide the total height of the water (3.125 inches) by the number of cans used (10) to determine the average height of water in each can (0.3125 inches).

 

Remember, you ran your system for 15 minutes. That means the stream applies on average 0.3125 inches of water in 1/4 hour. Multiply by 4 to determine the rate per hour (1.25 inches).
Remember, you ran your system for 15 minutes. That means the stream applies on average 0.3125 inches of water in 1/4 hour. Multiply by 4 to determine the rate per hour (1.25 inches).

 

If you'd like to know how long to run your system to apply an inch of water, divide 60 minutes (an hour) by the rate (1.25). To apply one inch per water, we would have to run our system for 48 minutes.
If you’d like to know how long to run your system to apply an inch of water, divide 60 minutes (an hour) by the rate (1.25). To apply one inch per water, we would have to run our system for 48 minutes.