Everything You Need to Know About Natural Pools: Design, Care & Costs

I’ve always dreamed of enjoying a refreshing swim in my own garden — but without harsh chemicals like chlorine. That’s why I find the idea of a natural pool so fascinating. In this guide, I’ll share with you everything I’ve learned about planning, building, and maintaining a natural pool, so you can decide if this eco-friendly oasis is right for you too.

Pure swimming pleasure without chemicals: More and more garden owners are fulfilling their dream of having a natural pool in their backyard. In this article, I’ll tell you what you need to know about building and maintaining a natural pool.

In natural pools (also called bio-pools) or swimming ponds, you swim without chlorine or other disinfectants — both systems work purely through biological processes. The difference lies in how the water is cleaned: in a swimming pond, plants do the cleaning; in a natural pool, it’s done by biological filters. A natural pool doesn’t stick out like an artificial element — with the right planting, it can blend beautifully into the garden like a pond. Here, I answer the most frequently asked questions about natural pools and what to consider for building and maintaining them.

What are the differences between a swimming pond and a natural pool?

Swimming ponds are generally large lined ponds with a dedicated swimming area and a separate regeneration zone full of aquatic plants. This planted area must be at least as big as the swimming zone. The plants keep the water clean thanks to a constant nutrient cycle: suspended particles settle, microorganisms break them down in the planting substrate, and plants absorb the released nutrients so they don’t feed algae — a living ecosystem without extra technology. It’s perfectly normal for a frog to swim by now and then or for the water to be slightly murky in spring and autumn. You’ll need to cut back the plants in autumn, occasionally vacuum the swimming area’s bottom, and keep the water surface clean. A depth of at least 2.5 meters is also essential.

Circulation pumps can speed up the water exchange between the regeneration zone and the swimming area. This means the planted zone can be smaller, making swimming ponds feasible even for smaller gardens. Mechanical surface skimmers help keep the water clean, but plants — and their care — are always required for a swimming pond.

A natural pool, on the other hand, can do without a planted filter zone entirely, although having one is an option. The water stays crystal clear because the pool functions like a flowing body of water: a pump pushes the entire water volume through a special sand filter and a phosphate filter several times a day. As long as the pump runs, microorganisms living in a biofilm on the filter grains break down nutrients, suspended particles, and especially algae food (phosphate). You won’t feel the flow while swimming.

What’s important when choosing the location?

A natural pool should be sheltered from the wind and ideally be in partial shade during the hottest part of the day (11 AM to 2 PM). Be careful with trees or large shrubs nearby: falling leaves add nutrients to the pool, which can harm water quality and encourage algae growth.

How is a natural pool constructed?

Like a swimming pond, a natural pool usually has a single-chamber system: the swimming area and the planted regeneration zone (or resting zone) are separated by walls that end about 40 centimeters below the water surface. Suitable materials for these barriers include plastic panels, stone, concrete, or fleece sacks filled with gravel.

A sturdy pond liner seals the pool. It’s protected from roots and sharp stones by a protective fleece and about 10 centimeters of fill sand. Plants in the regeneration zone grow in low-nutrient pond soil or a special substrate that binds nutrients. More advanced systems may include a separate clarification pond and a settling chamber next to the main pool. Filter pumps, usually housed in a pump chamber near the pool, keep the water circulating.

How big should a natural pool be?

The ideal size depends on how you plan to use it. For proper swimming, you’ll want a long, narrow swimming area with at least 35 square meters of surface area and a water depth of at least 1.8 meters. If you just want to splash around or cool off after a sauna session, 20 square meters of water area and a depth of 1.5 meters can be enough. You’ll also need a planted regeneration zone. By blending water and bog plants into surrounding flower beds and pebble shorelines, you can seamlessly integrate the pool into your garden.

A balanced ratio of swimming area to regeneration zone is about 1:1, so you’ll need at least 40 square meters in total. Smaller natural pools are possible, but their water quality can only be maintained with powerful filter systems.

How much does it cost to build a natural pool?

Costs vary greatly depending on your garden and your personal preferences. Extras like docks, islands, ladders, and advanced technology increase the price. If you hire a professional to design and build your pool, expect to pay between 150 and 400 euros per square meter. Professional companies — for example, members of the European Society for Natural Swimming Pools — provide not just the labor but also the expertise. If you build the pool partly or entirely yourself, you can cut costs to about 100 to 200 euros per square meter.

What can you do yourself without expert knowledge?

In principle, you can build everything yourself if you’re handy. However, due to the extensive earthworks, you’ll usually need a mini excavator and a few strong helpers. Less experienced DIYers can handle digging and planting themselves and hire a landscaping company for the liner installation and technical setup. Alternatively, you can buy a ready-made kit from a garden supplier, which comes with detailed instructions.

How much technology is needed?

Depending on your preferences and desired water quality, a natural pool can range from nearly technology-free to high-tech. A middle ground is to use basic equipment: a skimmer, a pump, and a filter. You can also add fine filters, channels, bottom drains, inlet nozzles, and lighting if you like — but the more you add, the closer you get to a conventional swimming pool (minus the chemicals). A minimum level of technology is sensible to prevent algae and reduce maintenance work. Too much tech, on the other hand, won’t necessarily improve water quality and can become a maintenance headache.

How much maintenance does a natural pool need?

No pool is maintenance-free! You’ll need to regularly remove leaves and, if necessary, string algae. A leaf net and algae skimmer make this easy to do yourself. Maintaining the equipment, like the skimmer and pump, is also straightforward after a short professional tutorial. Small debris on the liner can be removed with a simple pond vacuum. If the liner gets very dirty after several years, you can rent or buy a professional pond vacuum for deep cleaning.

What are the drawbacks of a natural pool?

Even though the water stays hygienic and crystal clear, a thin biofilm of tiny microorganisms will form on the floor and walls. This is unavoidable because, unlike in a chemically treated pool, these organisms aren’t killed off. They’re harmless but should be cleaned off regularly. A pool robot can do this automatically, often before you even notice the film.

My Conclusion

A natural pool brings swimming fun and a piece of nature right into your backyard — without the need for chlorine or harsh chemicals. With the right planning and care, it stays clear, clean, and inviting all summer long. I hope I’ve answered your main questions and inspired you to create your own little swimming paradise!

I hope I’ve been able to answer your most important questions about natural pools and that you now have a clearer idea of what to expect. For me, a natural pool is more than just a place to swim — it’s a piece of nature in my own backyard. If you decide to build one, I wish you crystal-clear water and countless relaxing moments in your personal paradise.