Converting an existing pool to a natural pool
Many US homeowners come to natural pools with a pool already in the yard. A conversion keeps some or all of the old shell and replaces chlorine with biological cleaning: usually a biofilter and phosphate filter, a darker finish, and either a planted zone dug beside the pool or a shallow end rebuilt as one.
Published US figures put a conversion at $50,000 to $175,000, which can be close to the cost of building new. The wide range reflects how much of the old pool is kept and whether a separate planted zone is added.
A conversion is worth looking at if
- Your pool shell is structurally sound and does not leak.
- Chlorine irritates your skin, eyes or lungs, or you dislike handling it.
- The pool needs resurfacing anyway, so a finish change costs less extra.
- There is space beside the pool for a planted zone, or a shallow end you could give up.
- You want to keep the pool where it is rather than dig a new one.
Typical conversion costs
| Item | Typical US range |
|---|---|
| Conversion, published US range Biofilter, finish and plumbing changes, with or without a plant zone | $50,000 to $175,000 |
| Removing an old pool Average, if starting again is the better option | about $6,000 |
| New planted zone, 300 sq ft Dug and lined beside the pool | $15,000 to $30,000 |
| Solar heating Installed, per the US Department of Energy | $2,500 to $4,000 |
| Permit and inspections Plumbing and electrical changes usually need one | $250 to $2,000 |
Typical US prices from two national cost guides published in 2025, read November 2026. National figures in US dollars, for the whole water area (swimming plus planted zone). A guide, not a quote. The new planted zone uses the same per-foot range as a new pool. See the cost guide to compare a conversion with a new build.
When building new is the better choice
A conversion is not always the cheaper route. If the shell leaks, the pool is very shallow (natural systems like depth), or the equipment pad is in the wrong place for new filters, the cost gap between converting and starting again narrows. Removing an old pool averages about $6,000 in national guides, and a new natural pool can then be placed and shaped for the biology from the start.
Ask a builder to price both. A good one will tell you if your pool is a poor candidate.
What usually changes in a conversion
The filtration
Sand or cartridge filters and the chlorinator come out; a biofilter, phosphate filter and low-speed pump go in.
The finish
Bright white plaster is often replaced or coated in a darker color that hides biofilm and looks more like natural water.
Copper and metal parts
Some heat exchangers, fittings and older ladders contain metals that can harm the biology; the builder checks and swaps them.
The plant zone
Either a new lined zone beside the pool, linked by a weir or pipework, or part of the pool rebuilt as a shallow planted shelf.
Draining and cleaning
Every trace of chlorine and stabilizer is removed before the biology is started.
Barrier check
If you are altering the pool, the inspector may check your fence and gates against current code.
Have a pool you want to change? Tell us about it.
Get a quoteHow a conversion runs
Inspection
The shell, plumbing and equipment are checked to decide what can stay.
Design
A hybrid filter, a planted zone or both, sized for your pool and climate.
Works
Draining, refinishing, new plumbing and filters, and the plant zone if there is one.
Restart
The pool is filled, the filter seeded, and water watched closely through the first season.
Common questions
Can any pool be converted to a natural pool?
Most concrete (gunite or shotcrete) and many vinyl and fiberglass pools can take a hybrid filter. Whether you can add a planted zone depends on space beside the pool. Very shallow pools are harder to keep cool and clear.
Does converting keep my pool the same shape?
If you use a biofilter, yes. If part of the pool becomes a planted shelf, the swimming area shrinks.
Can I keep my heater?
Often, if its heat exchanger is compatible. Many owners add or switch to solar heating, which the Department of Energy prices at $2,500 to $4,000 installed.
How long does a conversion take?
Typically a few weeks of work, plus time for the biology to establish after filling. Plan it outside your main swimming months.
Will my pool still need a fence?
Yes. Barrier rules apply to the water, not the treatment. See the CPSC barrier guidelines.
Get a quote to convert your pool
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.