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How To Make A Pond Safe For Swimming:  Safety Requirements, Testing And Treatment

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

When you visit your local lake, you may notice signs saying “No swimming”. 

There can be many reasons why you may not be allowed to swim in the lake, but generally all natural bodies of water are made for plants and fish. 

The same applies to your garden pond. It was designed to give your fish and water plants a home but ponds do not usually provide the best environment for people to swim in them. 

Deeper ponds and lakes can even pose a serious risk to life to swimmers, if they do not know the water conditions.

As a rule of thumb, you should only ever swim in bodies of water that you know well, and that have been tested and designed for swimming.

However, if you enjoy swimming in a more natural environment, then making your own large garden pool safe for swimming is a great option.

It allows you to take a dip in nature without leaving the comfort of your home.

But before you jump into your pond, there are a few things you need to do to ensure that your pond is safe for swimming.

In this article, we will explain how to create your very own swimming pond, and what you need to look out for to make sure that it is safe and healthy.

Health And Safety Risks In Swimming Ponds

There is a large number of dangers lurking underneath the surface of the water in ponds.

Let’s take a look at some of the most common health and safety risks in natural water.

Bacteria And Diseases

One of the biggest dangers in an outdoor pond is the large number of bacteria and possible diseases.

A pond is a freshwater ecosystem which provides a home to many plants and other animals.

They can produce and spread bacteria as well as a range of diseases.

Each water particle contains algae, bacteria, protists, zooplankton and fungi. 

Although the majority of these organisms do not cause any harm when they occur in limited numbers, some of them can cause serious health issues.

Diseases that are transmitted through water are typically found in freshwater that has been contaminated by wild animals that carry the diseases.

These water-borne pollutants are called pathogens. One of the most common pathogens are bacteria, including coliform bacteria and E. coli bacteria.

As these bacteria are carried by either wild animals and even your domesticated pets, then it is likely that your pond always contains these bacteria.

For a pond to be safe for swimming, you need to ensure that your pond has fewer than 150 colonies of E.

coli bacteria per milliliter of water. You can check this with a simple water test.

But there are also other pathogens which can be dangerous for swimmers.

Occuring on natural sediment and floating in the different layers of the water, protozoans such as Giardia and Cryptosporidium are naturally present in all freshwater.

However, in large numbers, these pathogens can lead to serious health issues in our digestive system and gut. 

And there are not just harmful creatures when you swallow the water.

Some tiny parasites that live in the water can also burrow through the skin which can lead to rashes, such as eczema or swimmer’s itch (also know as cercarial dermatitis).

How To Make A Pond Safe For Swimming:  Safety Requirements, Testing And Treatment

Dangerous Animals

Depending on where you live in the world, you may also find some dangerous animals wanting to share the pond with you.

From leeches and snapping turtles, to snakes and alligators, all these wild animals may enjoy your natural pond as a source of water or just to relax by the water edge.

Some of these animals have very sharp teeth that can cause serious flesh wounds.

Other wild animals, such as snakes or spiders may be poisonous, so it’s important you check your pond carefully before you get into the water.

In addition, a natural pond also contains a large variety of algal species that can be toxic when swallowed, particularly during the blooming season. They can cause stomach upsets and digestive problems.

Unsafe Ground

This may not look as dangerous as wild animals or harmful bacteria, but slippery and slimy ground when you get into the pond is one of the biggest causes of water-related accidents.

Ponds also usually contain stones, rocks and even logs that may have fallen from nearby trees.

All these can have sharp edges which can cut the skin of your feet and legs.

What Makes A Pond Safe To Swim?

Before we dive into the safety requirements for swimming ponds, it’s important to note that a pond will always be a natural environment with its own ecosystem.

This is what makes it very different from a chlorinated pool which is an artificial water system. 

Although ponds can be made safe for swimming, it is a different swimming experience because the pond will still contain fish and ornamental plants.

If you are happy with sharing your swimming space with them, then here is a quick overview on what constitutes a safe swimming pond.

Your Pond Should Be Large And Deep

In order to swim safely in a pond, you need to make sure that it is large enough to allow the swimmer to move freely.

You shouldn’t be able to touch any of the plants or the edges of the pond. This means that the pond needs to be long and deep enough.

The depth of your natural pool (see also ‘Natural Swimming Pools 101: Pros, Cons & More‘) is particularly important because it allows the swimmer to float freely.

If ever tried floating in shallow water, you will notice that you will start sinking very quickly.

You also need to ensure that the depth of the pond is right in order to avoid any scraping along the bottom where your pond plants live.

Typically, your swimming pond should have a length of at least 25 feet (though 30 feet is better) and a depth of 5.5 feet.

This allows a swimmer of an average height to swim without hurting himself or damaging the plant zone at the bottom of the pond.

You shouldn’t go any smaller with the recommended dimensions above.

The bigger your pond, the better for swimming as it gives you much more room for free movement.

Ensure Safety Of Pond Floor And Edges

Another safety concern for many ponds are the pond edges and floor. Wherever you enter and exit the pond should be well maintained to ensure that you don’t slip.

The same applies to the bottom of the pond. Depending on how deep your pond is, you should ensure that the area where you tread in the pond is safe to walk on.

Ensure Good Water Quality

This one is not just essential for your own wellbeing but it is also important for the health of your water plants and any aquatic animals living in the pond.

How To Make A Pond Safe For Swimming:  Safety Requirements, Testing And Treatment

Dirty ponds are often a sign of  bad water quality which shows in the excessive growth of algae and water-borne diseases as well as a large amount of bacteria.

In order to avoid this, it’s important to ensure the water quality of your pond is balanced. This will keep swimmers, as well as fish and plants, safe.

How To Increase The Safety Of Your Pond For Swimming

As we have seen, before you get into a pond, you need to make sure that it is safe.

Let’s find out how you can increase the safety of your pond and make it suitable for swimming.

Run A Good Quality Water Filter

Just like in a smaller aquarium tank (see also ‘The Best Canister Filters For Your Aquarium’), you should use a good quality water filter for your pond.

Bacteria and other pathogens only accumulate when the water quality is bad. In order to ensure your water is balanced, it’s essential that you install a fully-functional water filter.

This will reduce the large amount of pathogenic bacteria, and you can keep your water relatively clean.

This also means that the water will look clearer, which is nice for a little diving.

However, you will need to ensure that you have the right size filter. A filter that’s too small will not be able to handle filtering the large amount of water. 

A pond filter (see also ‘Best Pond Filter: Pond Pump For Garden & Koi Pond’) that’s too large may also filter out any of the good bacteria which is vital for the fish and plants living in your pond.

That’s why, make sure that you choose the filter based on the size of your pond.

Keep The Water Flowing

Sediment can only settle when the water is stagnant. However, if you keep the water moving with a water fountain or a waterfall, you can create an artificial current in the pond and the pathogens won’t settle anywhere.

In addition, you can also use a few pond pumps in some areas where you want the water to move around. This will also increase the oxygen levels in the water.

Ensure You Use A Good Water Source

Normally you expect the water coming out of your tap to be also suitable for your pond. However, this may not always be the case.

Sometimes also the source where you get your water from before you put it in the pond may be polluted with pathogens and contaminants.

This means that you will just add all these bacteria into your pond, harming fish, plants and potential swimmers.

Any pipes that feed water to your home, and ultimately your pond, may be a potential risk.

Particularly pipes that are near polluted water bodies, farms or processing plants may carry water that has been exposed to hazardous waste.

Check your water with a water test before you fill your pond, and if you notice anything unusual, then contact your local water authority.

Regularly Remove Any Insects And Floating Debris

Just like with any swimming pool, you will need to regularly remove any leaves, insects and floating debris from the surface of the pond as well as anything that has sunk further down.

While insects and leaves may be easy to remove, you will need to make sure that you also remove any debris that have sunk to the bottom of the pond, such as twigs and branches from overhanging trees.

It’s important to take all these debris out of your swimming pond as they could become a breeding ground for bacteria and other diseases.

The light debris do not only clog up the water filter, but they could also lead to a decrease in oxygen levels within the water, which will affect the plants and aquatic life in your pond.

How To Make A Pond Safe For Swimming:  Safety Requirements, Testing And Treatment

Frequently Check The Water Quality

This is one of the most important things you need to do at least once a week: check the water quality of your pond with a water test.

Although it is good to check and remove any debris that you can see in your pond, but there is a large amount of things floating in your pond water that are not visible to the human eye.

You will also need to make sure that the water quality is balanced, and this can be done only with a water test.

Usually the first signs of an imbalance ecosystem in your pond are large levels of nitrite and ammonia. You will also notice low levels of oxygen in the water.

It typically does take some time for these small signs to significantly damage the ecological balance in your pond, so by the time you notice anything, it is often too late to reverse any of the damage done.

That’s why, frequently check the water for the correct amount of elements in your pond.

Build Safe Stairs To Enter And Exit

The edges of a pond can be slippery due to algae growth and mosses, so it’s essential to build a safe set of stairs to get in and out of the pond.

This will prevent any injuries and falls.

As an alternative to a railed staircase, you can also build an elevated docking platform.

The dock should be slightly above the surface of the water, but safe enough for someone to step on.

Then you can attach a ladder to the dock so a swimmer can enter and exit the pond safely.

Remove Any Sharp Objects

In addition to removing any debris that may have fallen in, you should also make sure that there are no sharp objects in your pond before you fill it in, or when you change the water.

These objects may be rocks, wooden material that contain splinters or other objects with sharp edges.

Unwary swimmers may not notice these objects in the water, and this can lead to skin abrasions and other injuries.

Line The Pond Bottom

The floor of natural ponds is a breeding ground for worms, insects and other critters that may cause skin rashes, stings and wounds.

There are also a number of different plants or roots growing that may feel uncomfortable when standing on with your bare feet.

In order to avoid any unwelcome surprises, it’s best to line the bottom of your pond with some commercially available pond liner.

This will not just keep your feet away from the majority of animals that live at the bottom of natural water bodies, but it will also make cleaning your pond easier.

Fence The Pond Or Garden

Whether you naturally have wild animals stray into your garden or the neighbor’s cat, all animals carry parasites and bacteria which may end up in your pond.

Some of these animals may just be interested in your pond because they are thirsty, other animals, such as reptiles, enjoy living by a body of water.

This would make for a very unwelcome guest when you want to take a dip into your pond.

Although not all of these animals are dangerous and some may be easily removed, their waste products can still leak into your pond, which would put additional strain onto your water filtration system.

It’s best to put a fence around your pond or your garden to keep any animals, wild or domesticated, away from the water.

How To Make A Pond Safe For Swimming:  Safety Requirements, Testing And Treatment

Don’t Use Any Pesticides Near The Pond

Like any chemicals in water, pesticides can cause allergic reactions and skin irritations, so it is important that you do not use any chemicals or pesticides close to your pond.

Also bear in mind that a lot of chemicals can run off into the water, especially when it’s raining.

Use Only Suitable Swimming Pond Equipment

This may be surprising but a large amount of pond equipment is not suitable for swimming ponds.

This means that they may not have been officially approved, or they may lack important ratings to be safely used for swimming pools, including your swimming pond.

Check that any equipment you use for your swimming pond, especially electrical items, are suitable for this type of pond.

Supervision Is A Priority

Whenever you have a large body of water, it is essential that you supervise children nearby.

Pondside supervision can save lives, especially for children and adolescents who cannot swim.

Accidents are always a possibility, and it’s important that children are supervised by an adult who can react in case of emergencies.

You should also have a first aid kit and life ring nearby.

Choose The Right Plants And Fish

A pond is a natural habitat, and swimmers will enter this habitat of water plants, fish and other aquatic animals.

This means that you will need to be careful with the choice of your plants and fish. For example, you should choose plants that are not spiky or toxic.

The same applies for fish. The fish should not have sharp teeth, and they should be friendly enough to accept that they share their habitat with people.

Can You Swim With Ornamental Fish?

Yes, you can swim with ornamental fish. However, there are a few caveats with this.

It is essential for the healthy and safety of any swimmers as well as the fish in a swimming pond to ensure that the fish are well acclimated to people.

Two of the most popular fish species for ponds are goldfish and koi (see also ‘How Deep Should A Koi Pond Be?‘). Although these fish species are generally safe for ponds, they can develop stress symptoms when you swim with them.

A large number of recreational ponds use different ornamental fish species. Particularly koi carp can adjust well to being around humans.

However, you will need to provide a very large pond, and maintain water quality and its living environment to keep both fish and swimmers happy.

If you cannot provide a large enough habitat for your fish to safely swim when a human is around, then it is best to reconsider priorities.

Although we usually do keep fish as pets, they are not as accustomed to humans as dogs and cats are.

Fish prefer their own space, and they can get stressed when someone regularly enters their habitat.

It’s important to remember that splashes or sudden movement may scare fish, and they will hide very quickly.

When this happens frequently, then the fish may lose their appetite and they become more prone to diseases and health issues.

If you do decide to share the swimming pond with fish, then make sure that you do respect the fish and behave calmly.


A natural swimming pond can connect us to nature, and for anyone with a chlorine allergy caused by artificial swimming pools, swimming ponds are a great option.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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