Discovering a mysterious drop in your pool’s water level can be frustrating—and costly. If you own an inground pool, knowing how to find a leak in pool plumbingis essential to prevent structural damage, skyrocketing water bills, and inefficient filtration. You’re not alone: the average residential pool loses ¼ inch of water per day to evaporation—but anything beyond that often signals a hidden leak. This guide walks you through proven, practical steps to locate and address plumbing leaks before they turn into major headaches.
Why Is My Inground Pool Losing Water?
Before diving into leak detection, rule out normal causes. According to the Association of Pool & Spa Professionals (APSP), typical evaporation accounts for up to ½ inch of water loss per day in hot, dry climates. Wind, humidity, and pool usage also affect levels.
Quick Test: Perform a bucket test:
Fill a bucket with pool water and place it on the top step.
Mark both the bucket water level and the pool water level.
Wait 24–48 hours (with pump running normally).
If the pool level drops significantly more than the bucket, you likely have a leak.
If confirmed, the next step is determining whether the leak is in the shell (liner or concrete) or the plumbing system.
How Do I Know If the Leak Is in the Plumbing?
Plumbing leaks are trickier than surface cracks because they’re hidden underground. But here’s a reliable clue:
Water loss occurs only when the pump is running → Likely a pressure-side leak (return lines).
Water loss occurs only when the pump is off → Likely a suction-side leak (skimmer or main drain lines).
Constant water loss regardless of pump status → Could be either plumbing or shell.
💡 Pro Tip: Shut off the pump overnight. If the water stops dropping at a certain point (e.g., just below the skimmer), the leak is likely near that level in the plumbing or structure.
Step-by-Step: How to Find a Leak in Pool Plumbing (Inground Pool)
Step 1: Inspect Visible Components
Start simple. Check for obvious signs:
Wet spots or soggy ground around equipment pad
Cracks in exposed PVC pipes
Dripping valves or loose fittings
Air bubbles in the return jets (indicates suction-side air leak)
Step 2: Conduct a Dye Test (For Shell Leaks)
Use pH-neutral dye near fittings, lights, or seams. If dye gets sucked in, you’ve found a shell leak—not plumbing. Rule this out first.
Step 3: Isolate the Plumbing System
Turn off all suction and return lines using shut-off valves (if available). Then:
Plug skimmers and main drain with expandable plugs.
Plug return jets with winterizing plugs.
Monitor water level for 24 hours.
If water stabilizes, the leak is in the isolated section. If not, it’s likely in the plumbing under pressure.
Step 4: Pressure Test the Lines
This requires a professional-grade pressure testing kit (or a pro). The process:
Disconnect plumbing lines from the pump.
Seal each line with test plugs.
Inject air (15–20 PSI) into one line at a time.
Monitor pressure gauge for 10–15 minutes.
Pressure drop = leak in that line
⚠️ Note: Never exceed 20 PSI—PVC can crack. For accuracy, many technicians use hydrostatic testing (water instead of air) to avoid false positives.
💬 Expert Insight: “Most homeowners waste weeks chasing phantom leaks. A certified leak detection specialist can find and fix it in under 4 hours—with minimal digging,” says Maria Lopez, CPO® and owner of AquaScan Leak Detection (Austin, TX).
Maintain pH balance: Corrosive water degrades seals and metal parts.
Inspect annually: Especially before summer season.
Avoid landscaping near plumbing lines: Tree roots puncture pipes.
FAQ Section
Q1: Can I find a pool plumbing leak without digging?
Yes! Non-invasive methods like pressure testing, acoustic sensors, and tracer gas can pinpoint leaks without excavation. However, repair may still require digging.
Q2: How much does professional leak detection cost?
Typically $100–$500, depending on location and complexity. Many companies offer flat-rate diagnostics. Repairs range from $200 (simple fitting) to $2,000+ (main drain line under deck).
Q3: Will a small leak seal itself?
No. Even hairline cracks worsen over time due to water pressure and chemical erosion. Ignoring it risks sinkholes, foundation damage, or collapsed decking.
Q4: Does homeowners insurance cover pool leaks?
Rarely. Most policies exclude “gradual damage” like slow leaks. Sudden pipe bursts might be covered—check your policy.
Q5: How long does leak detection take?
DIY tests: 1–2 days. Professional detection: 2–6 hours. Repairs vary based on location and accessibility.
Q6: Can I use food coloring to find a plumbing leak?
Food coloring works for shell leaks (tile, liner), but not for pressurized plumbing lines. Underground leaks require pressure-based diagnostics.
Conclusion
Knowing how to find a leak in pool plumbing for your inground pool saves time, money, and stress. While some leaks are simple fixes, others demand expert tools and experience. Start with basic tests, isolate the problem, and don’t hesitate to call a certified technician if uncertainty remains. A well-maintained pool isn’t just beautiful—it’s safe and efficient.
Found this guide helpful? Share it with fellow pool owners on Facebook, Pinterest, or Nextdoor! Your tip could save someone thousands in water damage. 💧✨
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