Natural swimming pools
A swimming zone and a planted regeneration zone of about the same size, cleaned by gravel, roots and bacteria.
Natural Swimming Pool Builders
Will a natural pool work in your climate and yard?
Across most of the country, yes: natural pools were developed for cold winters and warm summers, and they do best where water stays below the high 70s °F. In the hottest states they still work, built deeper, shaded, or with a biofilter doing more of the cleaning.
Get a quote- $50 to $100 per sq ft of water, built
- No chlorine, salt or copper
- 48 in minimum barrier height in most codes
Four ways to swim without chlorine
Every natural pool uses biology rather than chemicals to keep water clear. What differs is how much of the work is done by plants and how much by a filter, and that decides the space, look and cost.
Hybrid and biofilter pools
The same chemical-free water from a compact biological filter, so the pool can keep a crisp shape and a small footprint.
Swimming ponds
Earth-shaped water with soft planted edges and a deep swimming area, for larger yards and acreage.
Converting an existing pool
Keeping a sound shell and replacing chlorine with a biofilter, a darker finish and, space allowing, a plant zone.
Whichever you choose, the upkeep is gardening rather than chemistry: see care through the year.
Natural pools by climate region
Heat, not cold, is what a natural pool has to manage. This is how the main US regions compare, and what builders change for each. Your plant list follows your USDA hardiness zone.
| Region | Fit | What to know |
|---|---|---|
| Northeast and Mid-Atlantic | Very good | The closest US match to the Austrian and German climates where natural pools began. Cold winters are fine; a full planted zone works well. Plan for leaf fall in wooded lots. |
| Midwest and Great Lakes | Very good | Short, warm summers and hard freezes. The pool stays full and can ice over. Minneapolis has run a public naturally treated pool since 2015. |
| Pacific Northwest | Very good | Mild summers keep water cool and algae slow. Conifer needles and shade need managing; water can stay chilly into June. |
| Mountain West | Good | Strong sun at altitude warms shallow water quickly, so depth matters. Check water rights and well supply for the first fill and top-ups. |
| Southeast and Gulf Coast | Possible, with care | Long, hot summers push water temperatures up. Builders lean toward hybrid systems, extra depth and shade. Warm untreated water carries a small Naegleria risk the CDC describes. |
| Desert Southwest and Texas | Possible, with care | Evaporation and heat are the challenges. Hybrids with shade structures are the usual answer; check local water restrictions before filling. |
| California coast | Good | Mild weather suits natural pools, but drought rules can limit filling, and state pool safety law asks for drowning prevention features on new pools. |
Natural or hybrid?
The first decision a builder will ask you about. Both are chemical-free; they differ in where the cleaning happens.
Planted natural pool
- How it cleans
- Gravel, plant roots and bacteria in a planted regeneration zone
- Space
- Plant zone roughly equal to the swimming area
- Look
- Part of the garden: soft edges, reeds and lilies
- Water clarity
- Improves over two or three seasons as plants establish
- Running needs
- Small pump; plant care each fall
- Best climates
- North, Midwest, Northwest, mountains
Hybrid with a biofilter
- How it cleans
- A biofilter and phosphate filter, with a small planted margin or none
- Space
- Close to a conventional pool footprint
- Look
- A defined pool, often with straight sides
- Water clarity
- Clear sooner; depends on the filter
- Running needs
- Longer pump hours; filter media replaced on a schedule
- Best climates
- Anywhere, and the usual choice in hot states
$40k–$80kfor a typical 800 sq ft family pool, half swimming, half planted
What a natural pool costs
Natural pools are priced by the whole water surface, plants included. National cost guides published in 2025 put them at $50 to $100 per square foot built, with most family projects landing between $50,000 and $150,000. The low end is a simple liner pool on easy ground; the high end has stone edges, decks, heating and difficult access.
| Total water area | Typical range |
|---|---|
| 500 sq ft | $25,000 to $50,000 |
| 800 sq ft | $40,000 to $80,000 |
| 1,000 sq ft | $50,000 to $100,000 |
| 1,500 sq ft | $75,000 to $150,000 |
| 2,000 sq ft | $100,000 to $200,000 |
On top of the build, budget for a permit ($250 to $2,000), a code-compliant fence where you do not have one ($2,000 to $13,500), and, if you want warmer water, solar heating, which the Department of Energy puts at $2,500 to $4,000 installed. There are no chemical bills afterward.
Typical US prices from two national cost guides published in 2025, read November 2026. National figures, a guide and not a quote.
Looking after it, season by season
The upkeep is real but light, and it is gardening rather than chemistry. Paid help, where you want it, runs about $15 to $260 a month in national guides.
March to May
Spring
Clear winter debris, restart or turn up the pump, clean the pre-filters and plant into any gaps. Test phosphate and clarity before the first swim; cool water slows algae, so spring is usually calm.
June to August
Summer
Skim most days, sweep the floor every couple of weeks and brush walls lightly. Watch temperature in heat waves: if the water clouds, add shade and ease off on big pool parties until it clears.
September to November
Fall
The busiest season. Net leaves before they sink and rot, cut back plants to just above water and take the cuttings away. A leaf net over the pool saves hours on wooded lots.
December to February
Winter
Leave the pool full. In freezing regions the pump is turned down or off and exposed pipework protected; in mild regions it ticks over at low speed. There is nothing to dose and no cover to wrestle.
It is still a pool in the eyes of the code
Plants and gravel do not change how building departments see deep water. In most of the US, local codes adopt the International Swimming Pool and Spa Code, which treats water more than 24 in deep as a pool needing a permit and a barrier. The CPSC’s barrier guidelines set out the same measurements. States can go further: Florida, for example, requires at least one of several safety features on every new residential pool.
- 48 inMinimum barrier height, measured on the side away from the pool
- 4 inNo gap in the barrier should let a 4 in sphere pass through
- 2 inMaximum gap under the barrier over grass or gravel (4 in over a hard surface)
- 54 inGate latches lower than this sit on the pool side, so small children cannot reach them
- SelfGates self-closing and self-latching, opening outward from the pool
How a natural pool is built
Design comes first. A builder visits to look at sun, shade, slope, trees and soil, and at how an excavator would reach the yard. From that comes a plan with the swimming zone, the planted zone or filter vault, and where the barrier and gates will go.
Then the paperwork. The plan goes to your city or county for a building permit, with electrical work and the barrier usually inspected too. HOAs often want to see the design. This can take weeks or a few months.
The build itself is a few weeks of digging, shaping, lining and plumbing. The swimming zone is typically 6 to 8 ft deep at its deepest, with planted shelves of 6 to 18 in. Stone or timber edges, decks and steps come last.
Filling and planting finish the job, ideally in spring or early fall so plants can root. The water often clouds or greens briefly while the biology settles; most pools look their best from the second summer.
What homeowners ask
What is a natural swimming pool?
A lined pool cleaned by biology instead of chlorine. Water moves from the swimming area through a planted, gravel-filled regeneration zone or a biofilter, where bacteria and plants remove the nutrients algae need. Our page on how a natural pool works explains it in full.
How much does a natural swimming pool cost?
National cost guides put natural pools at $50 to $100 per square foot of total water area, so a family pool of about 800 sq ft (half swimming, half planted) is typically $40,000 to $80,000. The cost guide works out a range for your size.
Are natural pools safe?
They are widely used in Europe and increasingly in the US, but the water is not disinfected, so it should be tested now and then and kept free of animals. The EPA recreational water criteria for fresh water are a useful benchmark, and the CDC advice for lakes and rivers applies.
Do natural swimming pools need a fence?
Usually yes. Most US building codes are based on the International Swimming Pool and Spa Code, which asks for a barrier at least 48 in high around pools more than 24 in deep. Some states add their own rules, such as Florida’s safety feature law.
Can I convert my chlorine pool into a natural pool?
Often, if the shell is sound. Most conversions add a biofilter and phosphate filter and change the finish; published figures run $50,000 to $175,000. See pool conversions.
Do natural pools attract mosquitoes?
Not when they are working properly. Mosquitoes breed in still, standing water; a natural pool circulates, and dragonfly larvae and other insects in the planted zone eat the larvae that do appear. The CDC has advice on standing water around the home.
How long does it take to build a natural pool?
Design and permits take a few weeks to a few months. Building is usually several weeks on site, and the planted zone takes one or two seasons to mature, so many owners plan the build for spring or early fall.
Get a quote
Three short steps: your ZIP code, the pool you are picturing, and how to reach you. Most people finish in under two minutes.
We are an introduction service, not a natural pool builder. You hear the builder's name from us first; we hold your details back until you say they can go.
Thank you. We have your details.
- By the next working day you should hear from us, by phone or email, with a natural pool builder who builds near you.
- If you are happy with that builder, say so and we pass your notes on. If not, nothing is shared.
- The builder visits the yard and prices the design with you. We will not send you newsletters or offers.