How to Detect Leaks in Your EPDM Pond Liner: A Comprehensive Guide

How to Detect Leaks in Your EPDM Pond Liner: A Comprehensive Guide

Ponds can be a beautiful addition to any property, providing a serene and natural environment for fish and wildlife. However, when a pond develops a leak, it can be a frustrating and potentially costly problem to address. In this comprehensive guide, we will walk you through the steps to detect leaks in your EPDM pond liner and provide you with practical solutions to fix them. 

Understanding Evaporation & Normal Water Loss

Before getting into the process of detecting leaks, it is important to understand the concept of evaporation and normal water loss in a pond. Evaporation occurs when water turns into vapor and escapes from the pond. During hot and dry weather conditions, it is normal for ponds to experience some water loss due to evaporation. In fact, it is not uncommon for water levels to drop by 1 to 2 inches per week in such conditions. But, if you notice a more significant and rapid loss of water, it may indicate a leak in your pond liner.

Checking for External Sources of Leaks

Before assuming that the leak is in the pond liner itself, it is essential to rule out any external sources of leaks. If your pond has plumbing inflows and outflows or features like fountains or waterfalls, carefully inspect these components for any signs of leaks. Make sure to check for loose connections, damaged pipes, or malfunctioning valves. If you find any issues, address them accordingly before proceeding with further leak detection.

The Water Leveling Method

One of the most effective methods for detecting leaks in a pond liner is the water leveling method. This process involves monitoring the water level in the pond to determine the location of the leak. 

Here's how to perform the water leveling method:

  1. Turn off all pond equipment, including the pump.
  2. Fill the pond to the top and let it sit undisturbed for 24 hours.
  3. After 24 hours, check the water level. If it has dropped, you likely have a leak in your pond liner.
  4. Examine the perimeter of the pond liner at the water level for any visible signs of damage such as gashes or tears.
  5. If the leak is substantial, it should be relatively easy to identify and assess the damage. However, tiny pinpricks or tears may require closer inspection.
  6. Consider using a non-toxic colored liquid, such as condensed milk, to create a visible trail leading to the leak. This can help pinpoint the exact location of the damage.

Patching Small Holes & Tears in EPDM Pond Liners

If you have identified a small hole or tear in your pond liner, you can often repair it yourself using a pond repair kit. These kits typically include primer, patches, a scrubbing pad, a roller, and disposable gloves. 

Here's a step-by-step guide to patching small holes and tears in your pond liner:

    1. Clean and dry the area around the damaged section of the liner using a rag that is dampened with acetone. 
    2. Apply Liquid Rubber Seam Tape to any seams, tears, or holes in the liner by peeling the backing film and pressing firmly to the repair area. Care should be taken to not allow wrinkles or bubbles in the Seam Tape. Once placed, press in the Seam Tape firmly with a laminate roller to ensure proper adhesion. 
    3. Apply Liquid Rubber EPDM Primer over the EPDM Liner (not the Seam Tape) in smooth, even coats. Allow the Primer to dry until it is tacky or dry to the touch, but do not leave it exposed for more than 6 hours before coating. 
    4. Once the primer has cured, it’s time to apply Liquid Rubber Neopond Sealant to the pond liner. Using a 3/8’’ (10mm) roller, apply approximately 3-4 heavy coats NeoPond Sealant. Allow at least 4-6 hours drying time between coats. You can recoat after the material is dry to the touch with nothing wet underneath and it is uniform in color. Apply each new coat at a different angle to the previous coat to ensure even coverage. For edges and corners apply using a nylon/polyester brush.
    5. Download our complete Application Guide Here

When to Consider Replacing the Pond Liner

In some cases, the damage to the pond liner may be too extensive to repair, or the liner may be old and weak with multiple leaks. If this is the case, it may be necessary to replace the entire pond liner. Replacing a pond liner can be a more involved process, and it is recommended to seek professional assistance or consult with a pond supply specialist to ensure proper installation and selection of a new liner that suits your needs.

Preventing Future Leaks and Maintaining Your Pond

Once you have repaired a leak or replaced your pond liner, it is important to take preventive measures to avoid future leaks and maintain the integrity of your pond. Here are some tips to help prevent leaks and ensure the longevity of your pond:

  • Regularly inspect the pond liner and surrounding areas for signs of damage or wear.
  • Keep the pond clean and free from debris that may puncture or damage the liner.
  • Avoid using sharp tools or equipment near the pond that could potentially cause damage.
  • Monitor the water level regularly to identify any sudden or abnormal drops that may indicate a leak.
  • Maintain proper water chemistry and filtration to prevent excessive stress on the pond liner.

Remember, early detection and prompt repair of leaks are crucial to minimizing potential damage to your pond and preserving its beauty and functionality.

Final Thoughts

Detecting leaks in your pond liner can be a straightforward process when approached systematically. By understanding the concepts of evaporation and normal water loss, checking for external sources of leaks, and utilizing methods like the water leveling technique, you can effectively identify and repair leaks in your pond. 

Whether you choose to patch small holes and tears or opt for a complete liner replacement, taking preventive measures and maintaining your pond will help ensure its longevity and enjoyment for years to come. 

If you encounter any challenges or have questions along the way, don't hesitate to seek guidance from pond supply specialists or professionals in the field. Now you have the knowledge and tools to detect and fix leaks in your pond liner, allowing you to continue enjoying the beauty and tranquility of your pond.

You can view our products and project pages at, and if you have any questions you can reach out to us at or by calling 1-855-506-2765.

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