Natural Swimming Pools More Viable as Climate Changes

When temperatures stay warmer through the winter, the plants that provide natural cleaning and filtration can continue to do their thing.

We just recorded the warmest late winter/early spring ever in much of the United States. If you’re of the opinion that this is likely part of the long-term Climate Change trend, not just a freak weather pattern, you might be thinking about what that means.

Let’s put aside the havoc this shift may play on flora and fauna for now, and zero in on a topic that gets a lot of interest every time we write about it: natural swimming pools. A lot of pool owners and would-be aquanauts have a certain “chemical anxiety” about their pools. They know that producing chlorine, muriatic acid and sulfuric acid have negative environmental impacts, and they want less chemical exposure when they swim or lounge by the pool

Chemical free natural pools do exist. But they require a delicate dance with water acidity, algae and pollutants, if they’re to remain clean and viable for occasional swimming.

The Link Between Climate and Natural Pool Viability

If you read what other people have experienced with their natural pools, you find that many ultimately give up and convert their natural pools back to chlorine- or salt-based filtration systems. Two big reasons for this are the short summer seasons in two thirds of the country, and the growth of unwanted algae.

Changes in climate, however, may shrink these concerns.


Most, but not all, natural ponds used for swimming tend to separate the filtration area from the recreational zone. This one was converted from a chlorine pool into a natural pool. Watch a timelapse video of the process.

Warmer zones are shifting further north, and the length (and severity) of winter cold snaps has shortened. Some research suggests that this trend is causing a “tropicalization” in many U.S. States, including Florida, Alabama and California.

In some forecasts, the temperate “niche” where humans can best thrive will move dramatically north over the next few decades, while the south half of the country becomes increasingly dry and hot.

Don’t misunderstand my point here. Man-made climate change has few silver linings. It’s likely to cause massive suffering and upheaval as people and wildlife migrate and attempt to adapt. Natural pools are just one minor line item on a short list of “positive” repercussions.

Plants to the Rescue

Here’s why. In order for natural pool filtration to work, plants have to do a lot of the clarification and processing of filtration. Only certain species of plants can survive an aquatic environment. Even fewer like cold-weather growth.

Think of a natural swimming pool more like a pond than a pool. I’m going to borrow a few examples from a list of highly effective, water-cleaning pond plants to give you a sense of how you might use aquatic plants to condition a natural swimming pool for most of the year, as conditions warm in your area:

  • Hornwort—This fully submerged bush grows 10 ft. tall, and inhibits algal growth.
  • Water Iris—Placed at the moist edges of a pond or pool, it soaks up excess nutrients.
  • Water Hyacinth—This surface plant soaks up bio pollutants, although it’s super aggressive, so keep it separate from main swimming areas
  • Soft Rush—Another marginal plant for pool edges, soaks up nitrogen and phosphorous, even sewage! Self seeding.
  • Water Mint—This plant cuts down on bacteria and heavy metals in water, growing up to 35 inches long, with colorful flowers.
  • Fanwort—A fully submerged oxygenator, Fanwort also removes CO2 and heavy metals from water.

These are just a few of the possibilities for making natural swimming pools more viable, as summer seasons grow longer and cold weather retreats.

Microclimates and Depth Matter

Keep in mind that many other variables can also make or break the viability of natural water basins. For example, you need a lot of direct sunlight in order for plant life to thrive.

Of course, sunlight also fuels algae growth, so you’ll need to strike a balance between algae-eating plants and sun siting. According to experts, your pool/pond’s volume is key. A large, deep pond is able to synthesize a lot of sunlight without major algae blooms. A shallow water basin, in contrast, will be harder to keep algae-free.

Climate change is scary stuff, but maybe we’ll be able to mitigate the change over the coming decades. Meanwhile, why not convert that traditional pool to one that will do less harm and can provide a calm and cooling haven for you and your family?

Publisher's Note: 2023 Outdoor Living Content is brought to you by Accoya, Pioneer, Provia and Unilock.

2024 Sustainability Symposium

webinar ad