A leaking pond or waterfall is every water feature owner’s worst fear—but with the right approach, most leaks can be found and fixed. The hardest part is often identifying where the leak is happening. A methodical process will save you time, money, and frustration.
TL;DR – How To Fix Pond and Waterfall Leaks: Follow These 5 Steps
- Pond leaks usually come from evaporation, edge leaks, plumbing issues, or liner punctures.
- Measure water loss accurately before diagnosing.
- Check for edge leaks first—they’re the most common.
- If water drops with the pump off, the leak is in the pond liner.
- If water drops only when running, the leak is in the stream or plumbing.
- Use proper EPDM liner patch kits for repairs—never foam or silicone.
- Plumbing leaks require digging along the pipe to find and replace the damaged section.
Water loss in a pond or waterfall is typically caused by one of four issues:
- Evaporation
- Edge leaks
- Plumbing leaks
- Liner punctures
Below is the step-by-step process professionals use to diagnose and repair leaks.
Step 1: Measure Exactly How Much Water You’re Losing
Before making any repairs, you need accurate data.
- Turn off autofill systems or valves.
- Measure water loss from a consistent point—the skimmer or pump vault works best.
- Track water levels over 6, 12, or 24 hours, and write the numbers down.
Understanding Normal Water Loss
All ponds lose water from evaporation. A running water feature typically loses 0.5%–1% of pump flow per hour. For example, a 3,000 GPH pump may lose 15–30 gallons per day to evaporation alone.
If your water loss exceeds normal evaporation levels, move on to leak detection.
Step 2: Check for Edge Leaks
This is the most common cause of water loss—especially in waterfalls and streams.
Look for:
- Damp or soggy soil along the pond or stream edges
- Water escaping behind rocks or boulders
- Low liner edges caused by shifting soil or settling
To fix an edge leak, rebuild the berm and raise the liner high enough to prevent overflow. Once adjusted, re-measure your water loss. If the issue stops—you’ve found your leak.
Step 3: Test the Pond for a Liner Leak
Turn off the pump and let the pond sit undisturbed for 24 hours.
What Your Results Mean
- If the water level stays the same: The leak is in the stream or plumbing.
- If the water continues dropping: The leak is in the pond liner.
Allow the water to drop until it stabilizes. The final waterline reveals the height of the leak.
Finding the puncture may require:
- Moving rock walls
- Cleaning debris away
- Carefully inspecting the liner
Use a rubber liner patch kit only—never silicone, foam, or non–fish-safe sealers.
Step 4: Test the Stream or Waterfall for Leaks
Stream leaks require water flow to diagnose.
Use a temporary flexible line from the pump to the first waterfall shelf. Run the water for 24 hours:
- If there’s no loss, move the temporary line up to the next waterfall level.
- Repeat until you discover the section where water loss appears.
Once the leaking area is found, remove rocks as needed and patch the liner with a proper EPDM patch kit.
Step 5: Inspect for Plumbing Leaks
If all liner tests come back clear, the remaining culprit is likely the plumbing.
Because pipes are buried, plumbing leaks may not appear as surface moisture.
How to check:
- Run the pump.
- Dig carefully along the plumbing line from the skimmer to the waterfall.
- Look for wet soil or flowing water underground.
After finding the damaged pipe or fitting:
- Cut out the compromised section
- Replace it properly—do not rely on tape, sealers, or temporary wraps
Those solutions only delay the problem and are not watertight long-term.
Need Help Finding a Leak?
If you can’t locate the problem—or don’t want the hassle of tear-down and repair—we’re happy to help.
Call 814-204-2721 or contact us online to schedule professional leak detection and repair.
