How to Measure Your Sprinkler System’s Water Output (The Tuna Can Test Guide)

Many Gulf Coast lawn problems aren’t caused by a lack of water — they’re caused by uneven watering.

If one section of your yard gets too much water while another gets too little, you may see fungus, thinning grass, or patchy growth. The good news: you can check your sprinkler system in about 15 minutes with a few empty tuna cans.

Supplies You’ll Need

• 3 or more empty tuna cans — or any flat-bottom container (about 1 inch tall)

• A ruler or measuring tape

• A timer or clock

Step 1: Set Up Your Cans

Place at least 3 cans in a straight line, starting near the sprinkler head and working outward to the farthest point it should reach. You can use more than 3, as long as they stay in a straight line. This shows whether water is spread evenly across the zone.

Step 2: Run the System

Turn on that irrigation zone for 15 minutes. This gives you a measurable baseline.

Step 3: Measure Each Can

Measure the water depth in each can. If one can has noticeably more or less water than the others, that sprinkler head may need to be adjusted, cleaned, or replaced.

Step 4: Calculate Your Watering Time

Use what you collected to figure out how long to run each zone to hit your weekly watering target.

Example: If you collect ¼ inch in 15 minutes, running that zone for 30 minutes will apply about ½ inch.

Repeat the test on each zone — spray heads and rotors put out very different amounts of water.

Printable Tuna Can Test Guide

Save or print this quick-reference guide to keep in the garage or next to your irrigation controller.

Why This Matters on the Gulf Coast

Sandy soils in Mobile and Baldwin Counties drain quickly, so small watering mistakes show up fast. Uneven watering can lead to:

• Lawn disease and fungus in overwatered areas

• Hot spots and dry patches where coverage is thin

• Weak, shallow turf roots

• Higher water bills

Measuring your output takes the guesswork out of watering. For how much water your grass type needs each week, see our guide: How to Properly Water Your Lawn in Mobile & Baldwin Counties.

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Need Help With Uneven Watering?

If you notice uneven coverage, dry spots, or excessive runoff, Southern Target can inspect and optimize your irrigation zones. Proper watering is one of the most overlooked parts of lawn care in South Alabama.

Call 251-414-7928 or text 251-244-7377 · Request service online

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