A beautiful yard doesn’t have to mean a sky-high water bill. But if you have an automatic sprinkler system, there’s a good chance you’re using more water than you need — and it’s costing you.
The good news? You don’t need fancy equipment or a professional irrigation audit to find out if your sprinkler system is wasting water. You can run a simple at-home test that I’ve recommended to Maryland homeowners for years. It’s quick, easy, and could save you hundreds of dollars over the season.
As someone who’s been working on yard drainage and landscape water management for over 40 years, I can tell you this: overwatering is one of the most common and overlooked problems in Maryland yards.
And it’s not just about the water bill. Overwatering causes: – Root rot in plants – Fungal lawn diseases – Increased mosquito breeding – Soil erosion and compaction – Runoff that carries fertilizers into storm drains
In other words, more water does not mean a healthier yard.
Why Overwatering Happens (Even With “Smart” Systems)
Many sprinkler systems are set up based on guesswork. Zones run for the same amount of time, regardless of whether they’re watering grass, shrubs, or shady areas. Sloped lawns, sunny patches, and clay-heavy soil all absorb water differently — yet most systems don’t account for that.
I’ve been called to homes where the front lawn was swampy, but the back was bone dry. Why? One timer controlling both zones equally. That’s like cooking everything in the oven at 400° — no matter what it is.
Some other common reasons for waste: – Broken or misaligned sprinkler heads – Overspray onto driveways, sidewalks, or fences – Watering during wind or midday sun (increased evaporation) – Running too long, too often – Leaky valves or underground pipe cracks
Even the latest “smart controllers” won’t fix these issues if the system isn’t designed and maintained properly.
The Simple Tuna Can Test
This old-school trick still works — and it’s shockingly effective.
What you need: – 4 to 6 empty tuna cans or similar-sized containers – A ruler or measuring tape – A stopwatch or timer
Steps: 1. Place the cans evenly around one sprinkler zone (make sure they’re on level ground). 2. Run the sprinkler for 15 minutes. 3. Measure the water depth in each can and calculate the average.
Interpretation: – Lawns generally need 1 inch of water per week, including rain. – If your zone puts out more than 0.25” in 15 minutes, you might be overwatering. – If the coverage is uneven (some cans have twice as much as others), you have a distribution problem.
Run this test on each zone — especially those with different types of plants, slopes, or sun exposure. Don’t assume all areas of your yard need the same amount of water. Most don’t.
Want to take it a step further? Measure the output after making adjustments to your heads or timers, and compare. You’ll likely see just how inefficient things were before.
Bonus Test: Soil Saturation Check
Right after watering, take a long screwdriver and push it into the soil. It should go in easily to at least 6 inches. If not, you’re not watering deeply enough — and that leads to shallow roots and more frequent watering.
Healthy roots grow deep. And deep roots mean better drought tolerance and fewer weeds.
You can also dig a small test hole and feel the soil with your hand. If the top is soaked but it’s dry 4 inches down, that’s a red flag. You’re getting surface water — not deep irrigation.
Watering Tips for Maryland Soil and Weather
Maryland homeowners face a unique mix of challenges: heavy clay soil in many regions, unpredictable storms, and humid summers that invite disease.
Here’s what I recommend:
- Water early in the morning (4–8 a.m.). This reduces evaporation and gives grass time to dry before nightfall, preventing fungus.
- Avoid watering after heavy rain. Install a rain sensor or use a weather-based controller. Maryland averages 42” of rain per year — your system should know that.
- Adjust for slope. Sloped areas need shorter, more frequent cycles to avoid runoff. Break watering into 2–3 short sessions (cycle and soak method).
- Don’t water every day. Lawns do better with deeper, less frequent watering. Twice a week is plenty for most lawns.
- Use mulch in planting beds. It holds moisture, regulates temperature, and reduces the need to run sprinklers.
- Audit your system every season. Heads shift, plants grow, and valves wear out. What worked last year may not work this season.
Signs Your Sprinkler System Is Wasting Water
In addition to the tests above, here are clues that your irrigation is working against you:
- Wet sidewalks or fence lines after watering
- Brown spots in some areas, soggy patches in others
- Runoff into the street or driveway
- Sprinklers still running while it’s raining
- Grass that feels spongy or shows signs of disease
- A sudden spike in your water bill
You’d be amazed how often I find a broken head blasting water straight into the bushes — and no one notices for weeks.
How to Fix a Wasteful System
Here’s what I recommend to clients who want a smarter, more efficient sprinkler setup:
- Adjust zones individually. Shrubs, shaded areas, and different soil types need different watering schedules. Don’t treat your yard like a single crop.
- Replace broken or mismatched heads. Use the same type and brand across zones for consistency.
- Tune the arc and spray pattern. Heads should spray only where needed — not on the driveway.
- Upgrade to a smart controller. These systems adjust based on weather, season, and soil data. Huge savings with minimal effort.
- Add pressure regulators. Too much pressure causes misting and uneven coverage.
- Install drip irrigation in beds. Far more efficient than overhead watering. Drip delivers water directly to the root zone.
How AskBobCarr.com Can Help
You don’t have to tackle this alone. At AskBobCarr.com, I’ve spent decades helping homeowners like you optimize their yards — not just for looks, but for long-term health and efficiency.
I don’t sell sprinkler systems. I don’t represent a manufacturer. What I do is help you understand what’s really happening underground — and how to fix it smartly, not just expensively.
Whether it’s rerouting runoff, fixing erosion, or adjusting irrigation to match your property’s contours, I’ve got the tools and the experience to help you do it right the first time.
Final Word from Bob Carr
Sprinkler systems are meant to make life easier — not waste money or water. This simple at-home test gives you real insight into what your yard actually needs. And that’s what I’m all about at AskBobCarr.com: giving Maryland homeowners the knowledge and tools to make smarter decisions.
Before you invest in upgrades or live with brown spots another season, start with the tuna can test. It’ll show you more than you think.
Take the Next Step
Download your free checklist:
↓ Sprinkler System Water Waste Checklist (.docx)
Related reading:
How I Diagnose Yard Drainage Problems in Maryland Yards (My 42-Year Method)
Still unsure? I’ll walk the yard with you.
Visit AskBobCarr.com to schedule a yard drainage consultation or irrigation walk-through. Let’s make your yard healthier, smarter, and easier to maintain.
Remember: More water doesn’t always mean better. Sometimes, it just means waste.
Let’s fix that — together.