Sprinkler Catch Test Sheet
Five tins, one timed run, a ruler. Take the rate to the watering calculator; act on the uniformity at the heads.
BFCBrilliance · bfcbrilliance.com/tools/sprinkler-coverage-test-calculator
The arithmetic
- Average depth
- add the five tins ÷ 5
- Output rate
- average ÷ minutes x 60
- Uniformity
- driest ÷ average x 100
- Shortfall at the dry spot
- 100 − uniformity
- Spread
- wettest ÷ driest
- Rate at the driest spot
- driest ÷ minutes x 60
- ⚠ Straight-sided tins only
- tapered ones read wrong
- ⚠ A tin catching nothing
- is a coverage GAP, not a ratio
- Then plan run times
- with the watering calculator
One row per zone - retest yearly
| Zone | Minutes | Average | Driest | Rate in/hr | Uniformity % |
|---|---|---|---|---|---|
This test
- Date
- Zone
- Minutes run
- Tin 1
- Tin 2
- Tin 3
- Tin 4 (edge)
- Tin 5
- AVERAGE
- DRIEST
- WETTEST
- OUTPUT RATE
- UNIFORMITY %
- Action taken
Running the test properly
- Straight-sided containers, not tapered
- Five of them, spread across the zone
- One placed near the EDGE of the throw
- None sheltered by shrubs or overhangs
- Still conditions - wind measures the wind
- Zone run for a measured time, not an estimated one
- Depths read with a ruler, not judged by eye
- Each zone tested separately
- Rate written inside the controller cover
- Retested after new nozzles, heads, pressure changes or repairs
The average hides the problem
A zone can average exactly the right depth and still have a corner receiving a fraction of it. Watering longer makes the wet end wetter and leaves the dry end proportionally just as short. Uniformity is the figure that tells you whether any single run time can work at all - and if it cannot, the fix is at the heads.
This measures, the other one plans
Take the output rate from this sheet to the Lawn & Garden Watering Calculator, which turns a rate into run times and gallons for a lawn of a given size. Two tools, one job each - measure first, then schedule.