Keep Your Yard from Turning Into a Swamp by Finding and Fixing That Pond Leak

Get Your Pond Back in Line

Leaky ponds are terrible for many reasons, some of which you may be experiencing right now—much like the soggy soil you’ll see along low paths in Patapsco Valley State Park after a storm. A pond leak can lead to a swampy yard, higher water bills, and more stress. This is why pond owners want to know how to find and fix pond leaks quickly.

If you have a leaking pond problem, there are several ways you can fix it. Most issues are pond liner leaks, which you can usually fix.

Find out how you can fix your leaking pond and pond liners below.

Quick Pond Leak Diagnostic Checklist

Before you start draining water or moving fish, it helps to narrow down where the issue might be coming from. Most leaks reveal themselves through a few tell-tale signs, just like the way runoff finds the same low spots along the Chesapeake & Ohio Canal every heavy rain.

Here are some quick checks you can do up front:

• Look for soggy areas around the outside edges of the pond, especially behind the waterfall or along stream banks.
• Watch the pond closely with the pump on and off—if you lose more water while the system is running, the leak is likely in the stream, waterfall, or plumbing.
• Check the skimmer to see if the water level drops below the opening.
• Inspect areas where the liner folds or edges may have settled.
• Follow any visible wet streaks in the soil, as they often point directly to the leak source.

How To Find a Leak in a Pond Liner

Finding a pond leak is the first step to fixing the problem. If you’re losing water, this actually makes the process easier.

1. Move your fish into a separate tub filled with their old water in case the leak is near the pond bottom
2. Turn off the system and any extras, like an auto-fill device
3. Fill the pond up to the normal level
4. Allow the pond water to drain
5. When the water stops, check the water line for the source of the pond leak, such as low edges, pond liner tears, failed skimmer seals, etc

If the water level only drops a bit or doesn’t drop, the leak isn’t in the pond basin. This means it’s somewhere else, and you’ll have to go searching for it another way.

Many leaks are found by searching on hands and knees, looking at the pond liner for any damage.

Using Milk to Find a Leak In a Pond Liner

You can use a gallon of milk or some non-toxic dye to find a pond leak.

Let the colorful liquid run from the top of the feature.

Watch where it goes, as it’s likely to leak out with the other water where the damage is.

Don’t be shy about pouring it in; the leak area could be small and hard to see.

Once you find the leak, you can determine the best way to fix it.

Contact us to investigate your pond today.

How To Fix a Leaking Pond Using Liquid Rubber Products

Here’s one way you can fix a pond liner leak using a certain liquid rubber product.

1. Drain the water down to about 6 inches
2. Remove any fish and plants
3. Place the fish in a shaded tub filled with their pond water
4. Drain the rest of the water
5. Clean the pond bottom of muck, sediment, and anything else
6. Remove any repair patches if there are any
7. Pressure-wash the liner
8. Allow it to completely dry
9. Use a liquid rubber seam tape on the damaged area
10. If you have an EPDM liner, clean it with acetone and then use a liquid rubber EPDM primer
11. Use a sprayer, roller, or brush to apply a liquid rubber sealant to the affected area
12. Allow the coat to dry completely
13. Apply 2 to 3 more coats or until you reach a 30 mil. thick membrane
14. Allow 3 to 5 days for drying
15. Refill your pond
16. Wait 24 to 48 hours to see if there are any leaks still
17. Treat the water so it’s good for your fish
18. Put your plants back
19. Properly reintroduce your fish to the water

Other Ways to Fix a Pond Leak Based on the Type of Damage

Many leaks are pond liner leaks, meaning something is wrong with your pond’s liner—just like when a root pushes through the edge of a water feature at the U.S. National Arboretum.

There are many causes for pond liner leaks. Before you fix the leak, make sure you take care of whatever caused it.

Here’s how you can fix the common leaky pond problems.

Pond Sealant for Small Holes in a Pond Liner

If the damage is only 1 to 2 inches, this is a great way to fix it. Pond sealant is safe for fish and aquatic plants.

Here’s how to use it:

1. Remove fish and plants
2. Drain your pond
3. Dry the damaged area
4. Apply the sealant as the directions say
5. Wait for it to cure

It can take up to 8 hours to cure, so if you have any fish, you may want to do this earlier in the day. Then they won’t have to stay in a tub all night. They’ll need shade and an aerator to be comfortable.

Repair Kits for Larger Holes in a Pond Liner

This is a patch for holes ranging from 2-by-2 inches all the way up to 30-by-30 inches. Most kits come with primer, a sticky patch, and a roller.

It’s quite easy to do:

1. Remove fish and plants
2. Drain your pond
3. Dry the area
4. Apply the primer
5. Cut the patch into a circle
6. Apply the patch using the roller
7. Wait for it to set

Patches tend to blend in pretty well, so it’ll be hard for people (and maybe even you) to tell where it is.

When You Need to Add Pond Liner

Sometimes, you just need more pond liner. That’s where joining tape comes in. It’s sticky on both sides, so you can stick two liners together.

You can also use it for smaller damages and to reseal skimmer boxes.

Here’s how to do it:

1. Clean and dry the pond liner
2. Apply primer
3. Use joining tape on the liners
4. Let it set
5. Tuck it back into place

You may need to shore up the area more so you don’t fix one leak just to have another come up.

Extra Large Pond Liner Damage

If your pond liner is damaged beyond repair, you’ll need to replace it.

This involves emptying the entire pond, taking anything off the liner, and replacing it. This is one way to get rid of any pond liner leaks, whether you see them or not.

Fixing Leaks in Large Ponds

These are solutions more fit for larger backyard and farm ponds as opposed to backyard garden ponds and koi ponds.

Add Water to Your Pond

This isn’t a real solution, but if your pond is large and the leak is small enough, you can just pump in water overnight. Check with local authorities to see if you need a permit, as it may be a requirement if your groundwater withdrawals exceed 10,00 gallons daily.

Compact the Soil

Sometimes, a leak can be loose or aerated soil, allowing water to seep through. Fixing this is a big project.

You’ll need to first fully drain the pond.

Then, remove debris at the bottom of the pond.

Till the bottom 12 to 16 inches deep.

Finally, compact the bottom with a roller. The compacted layer should be 6 inches in shallower areas and 12 inches in deeper ones, usually 10 feet and deeper.

Add Clay

Clay isn’t permeable, meaning water can’t seep through it—just like the natural clay layers that hold water beneath the wetlands at Blackwater National Wildlife Refuge. This makes it ideal for stopping leaks in ponds.

You’ll need to follow the same process as with compacting the soil.

The material you add needs to be at least 20% clay. It’s preferable to spread it in 1-foot layers after you compact it.

Bentonite

Bentonite is a clay-like material that expands when wet, making it ideal for sealing cracks and holes.

To fix a pond leak with bentonite, first, make sure the area around the leak is dry.

Then, apply a layer of bentonite to the area and wait for it to dry.

Once it has dried, you can then add water to the pond.

The bentonite will swell and seal the leak.

This method can be used for both superficial leaks and leaks that are deeper in the pond.

While it is not a permanent fix, it can help to prevent further leakage and damage to your pond.

Bentonite is also effective at absorbing toxins and unwanted particles from the water, making it an ideal way to keep your pond clean and healthy.

Chemicals

There are various chemicals you can add to the soil in and around the pond to help fix leaks. One of these is sodium polyphosphate.

Sodium polyphosphate is an inorganic compound made up of sodium, phosphorus, and oxygen. It is commonly used as a fertilizer, food additive, and industrial cleaning agent. Sodium polyphosphate can also be used to fix pond leaks.

When added to the soil around a leaky pond, the sodium polyphosphate helps to bind the soil particles together, making the soil less likely to erode.

The phosphorus in the sodium polyphosphate also helps to encourage the growth of grass and other plants, which can further help stabilize the soil.

While sodium polyphosphate is not a permanent fix for a pond leak, it can help to temporarily repair the problem and prevent further damage to the pond.

Add Pond Liner

Adding a plastic or vinyl liner is one of the most effective ways to fix a pond leak.

The liner will create a barrier between the water and the soil, preventing further leakage. 

They’re better for smaller ponds or ponds with bad leaks that happen repeatedly.

While it’s highly effective, it’s also on the expensive side.

Pros and cons of owning a koi pond.

When It’s Time to Stop DIY and Call a Professional

While many pond leaks can be handled with careful testing and a little elbow grease, some situations need a trained eye.

If the waterline test doesn’t reveal anything, or the water only drops when the pump is running, there’s a good chance the leak is hiding somewhere in the waterfall, streambed, or plumbing—areas that often require more specialized tools to pinpoint.

It’s also best to call in a pro when the liner is older, brittle, or showing multiple weak spots, or when the pond keeps leaking again after you’ve already patched it.

Any time the leak is deep in the pond or involves old skimmer boxes, bulkheads, or underground lines, professional help will save you hours of digging, guessing, and refilling.

Most Common Leak Causes in Maryland Ponds

Maryland ponds tend to leak for a handful of very predictable reasons—many tied to our climate and landscape.

Freeze/thaw cycles in winter can make liners brittle over time, especially in shaded areas that stay cold longer, similar to the icy patches that linger along the paths at Patapsco Valley State Park.

Tree roots are another major culprit. Roots from river birch, willow, and maple trees love to chase moisture and can push right into a liner seam.

Heavy spring and summer storms also wash out soil around pond edges, lowering the liner and letting water escape without you noticing.

Wildlife can get involved, too; raccoons stepping on stream edges or herons landing near shallow areas can tug the liner down just enough to start a slow, steady leak.

How to Prevent Future Pond Leaks

Once you get your pond watertight again, a few simple habits can help prevent you from running into the same issue next season.

• Supporting the pond edges with compacted soil or stone keeps them from settling after heavy rain.
• Keeping trees with aggressive roots a safe distance away or adding a root barrier can also protect your liner long-term.
• Regularly checking the waterfall edges, especially after big storms, helps catch problems before they turn into major leaks.
• Cleanouts in spring and fall remove debris that can trap moisture against the liner.
• Inspecting your skimmer seal once or twice a year prevents slow drips from sneaking up on you.

You Can Trust the Experts at Premier Ponds to Quickly Find and Fix Your Pond Leak

If you have a pond on your property, it’s important to make sure that it is properly sealed and waterproof. A leaky pond can cause all sorts of problems, from structural damage to the surrounding area to serious health risks for your fish and other aquatic creatures.

That’s where Premier Ponds comes in. We have the expertise and equipment to quickly find and repair any leaks in your pond, whether it resembles the quiet garden ponds at Brookside Gardens or the stone-lined water features near Great Falls Park.

So, don’t wait until it’s too late – fill out our contact form today. We promise you won’t regret it!