A swim pond works the other way round. Rather than separating the swimming water from the garden, it integrates planting directly into the system, using a dedicated regeneration zone of marginal and submerged plants to manage water quality biologically instead of chemically. The swimming zone and the planted zone share the same body of water, connected by circulation, so the pond behaves as a single living system rather than a controlled tank sitting apart from the garden around it. Visually, this tends to mean a swim pond reads as a garden feature first and a place to swim second, whereas a pool usually reads the other way round.

A pond, and particularly a swim pond, is a considered purchase most homeowners make once. There is no easy way to test-drive a designer before committing, which is why credentials tend to carry more weight in this kind of decision than they might for a smaller, lower-stakes purchase. Three accreditations worth understanding, and worth asking any designer about directly, are BALI membership, CHAS accreditation and ISO 14001.

The regeneration zone is the part of a swim pond that does the quiet work, and it sits at the centre of what this business calls the Michael Wheat System. Rather than one single feature, the term describes a considered combination of planted filtration, water treatment and circulation designed to work together, and the regeneration zone is where the biological side of that combination happens. It is worth being clear from the outset: the Michael Wheat System is proprietary, branded terminology used to describe this business’s own design approach. It is not a patented process, and no claim is made that it is legally protected as one.

The idea that a garden pond can be clean enough to swim in without chlorine or any other chemical treatment sounds, to a lot of people hearing it for the first time, like a stretch. It is worth setting out plainly why it works, as a matter of ecological design rather than as any kind of health or medical claim about swimming water generally.

CHAS accreditation deals with a different, more practical question: health and safety compliance. CHAS assesses whether a business meets recognised health and safety standards, which matters directly on a garden project involving excavation, plant machinery, water and often working close to a client’s home. Asking whether a designer holds CHAS accreditation is a reasonable way to gauge how seriously health and safety is treated on site, before any work begins rather than after something goes wrong.

UV treatment adds a further layer on top of planting and circulation. As water passes through a UV unit, ultraviolet light disrupts the reproductive ability of free-floating algae cells, which helps keep the water column clear even in warmer months when algae growth would otherwise accelerate. It is worth being precise about what UV treatment does and does not do: it acts on algae suspended in the water as it passes through the unit, it is not a chemical treatment, and it does not replace the biological role the regeneration zone plays. Think of it as support for the planted system during the periods when algae pressure is highest, rather than the primary mechanism keeping the pond clear.