Major pond maintenance | The most important tips, tricks and facts
A pond that is several years old needs major maintenance over time. This is because after a number of years a layer of mud can build up on the bottom of the pond, causing pond water to become contaminated and aquatic plants no longer grow properly. Annual maintenance is no longer enough in this case, larger measures are needed such as draining, repurposing with aquatic plants and refilling the pond with clean water. Find out all about major pond maintenance? Then read on.

All about large pond maintenance
- The importance of great pond maintenance
- The reasons for major pond maintenance
- Large pond maintenance roadmap
- Why pond maintenance alone is not enough for a healthy pond
The importance of great pond maintenance
Major pond maintenance is important to maintain the health of every pond type preserve and extend its life. If too much mud and waste accumulates at the bottom of the pond or if pond plants overgrow the pond, this can lead to poor water quality, lack of oxygen, algal blooms and fish diseases. Major maintenance, which involves completely emptying and cleaning the pond, can help solve these problems and return the pond to a healthy, clear state.
Aquatic plants are a must have
No natural pond without aquatic plants. Aquatic plants provide a clear and clean pond naturally. With a natural pond you do NOT burden the environment, help restore biodiversity and create a beautiful watering hole in the garden. - Simon
Hardy pond plants from our own plant nursery
The reasons for major pond maintenance
Improving water quality
By completely emptying and cleaning the pond, accumulated mud, waste products and excess nutrients can be removed. If this is not done once every four years, the pond water will suffer from excessive algae formation green coloring what the pond and the pond fish and others pond animals will not benefit.
(EPDM) pond liner
If you pond liner of PVC and it has become porous, major maintenance may be necessary. In fact, after five to ten years, PVC liner can become porous and the pond starts to leak. The only solution then is to install new liner. Fortunately, rubber liner has a much longer lifespan than PVC liner, so you won't run into problems with it.
Overgrown aquatic plants
When aquatic plants overgrow the pond, simply pruning back is often no longer an option. In that case, you must take a more rigorous approach and empty the pond completely to remove the aquatic plants, especially their stubborn root systems, from the pond. It seems like a big job, but the result is a pond that is healthy and balanced again.

Large pond maintenance roadmap
Step 1: Emptying the pond
Draining a pond is a big job best done in the fall or early spring. To empty the pond, you'll need draining equipment, such as a dirty water pump and a hose that you hang in the sewer drain. Start by pumping the pond half empty before you begin removing your fish and aquatic plants. Be sure to keep them in the original pond water in a separate container so they are safe while cleaning the pond.
Step 2: Removing the mud layer
Once the pond is drained, it is time to carefully remove the mud layer from the bottom, without damaging the liner. Also remove as much as possible of the roots of aquatic plants in the mud. Aquatic plants or cuttings you want to keep can be planted back into planting baskets. A drained pond provides an opportunity to check the pond liner. Consider replacing the entire liner, especially with PVC liner, now that the pond is empty anyway.

Step 3: Setting up the pond
Now that the pond is completely empty and clean, it's time to redecorate it. Choose the right aquatic plants to place in the pond and add any old plants that are still intact. Be sure to choose aquatic plants with different functions so they can optimally filter the pond water and keep it healthy. Don't just consider oxygen plants, but also add marsh plants, water lilies, floating plants and other aquatic plants to keep the pond balanced.
Hardy aquatic plants from our own plant nursery
Step 4: Filling the pond with water
The water level in the pond will change over time. In hot summers with lots of sun, water evaporates, so the water level drops. It is necessary to refill your pond with water as soon as this happens. This ensures that the pond liner is not exposed to sun and other weather influences and prevents leaks from occurring as quickly. A good water level is also essential for your pond plants. Do not fill your pond all at once, but spread smaller amounts of water over several days. This will best maintain the biological balance in your pond. You can use either ground water or tap water.
Step 5: Starting up the pond
Start up the pond by adding pond bacteria to the water. Pond bacteria provide a good start because although they are not visible to the naked eye, pond bacteria play a crucial role in maintaining a healthy pond. These microorganisms are vital to the biological balance of any water feature and help keep your pond clean and clear year-round.
Why pond maintenance alone is not enough for a healthy pond
Major pond maintenance is necessary because seasonal maintenance is not always sufficient to ensure the long-term health of the pond. Maintenance such as leaf removal and water refilling is important, but if too much mud and waste accumulates at the bottom of the pond, it can lead to poor water parameters and problems for fish and other aquatic animals. In addition, aquatic plants may overgrow the pond, necessitating intervention. Also, pond liner may become porous after several years and need to be replaced. Major maintenance, which involves completely emptying and cleaning the pond, can help solve these problems and restore the pond to a healthy, clear condition. So seasonal maintenance is a good basis, but major maintenance is necessary to keep the pond in top condition.
Frequently asked questions about major pond maintenance
The best time for major pond maintenance is usually in the fall or early spring, when water temperatures are still relatively low and there is less chance of harmful algae blooms.
To remove the mud layer, it is advisable to drain the pond. Make sure that you do this carefully without using sharp objects so as not to damage the pond liner. Once the layer is removed, you can rearrange the pond and fill it with water.

Simon van der Velde
Pond specialist and aquatic plant grower since 1986
Simon's vision is to let nature do its work in your pond. No need to buy all kinds of measuring equipment and water improvers. If the fish are swimming nicely and the plants are growing well, then the water in the pond is of good quality. With a good planting plan and the right approach, you can save a lot of money and maintenance, and ensure a clear, biologically balanced pond that becomes more beautiful every year.