Does an overflow pool use more water than a skimmer pool?

No — the water that spills over is caught in the channel and recirculated, not lost. Evaporation runs slightly higher than a covered skimmer pool, mainly because the moving sheet at the edge exposes a bit more surface.

Can I add an overflow edge to an existing skimmer pool later?

Realistically no, not as a simple retrofit. The channel, the balance tank and the millimetre-level coping are structural decisions baked in from the start — treat overflow as a rebuild, not an upgrade, and decide before construction begins.

Is skimmer water actually dirty?

No — it's good, just not quite the best possible. A well-run skimmer pool with a weekly brush and a nightly cover looks perfectly clean to anyone who isn't a pool engineer.

Can a raised pool use either edge system?

Yes — the edge system and the rim height are independent choices. A raised pool can skim from its wall units or overflow at its top edge exactly like an in-ground one.

Which is easier to keep clean day to day?

Overflow, mechanically — nothing sits waiting to be emptied. A skimmer pool asks a few minutes of basket-emptying now and then in exchange for a much simpler structure underneath it.

Skimmer vs deck-level overflow pools

The two dominant edge systems compared: cost, water quality, looks and what each means for your build.

Every pool needs an edge system, and this is the decision that decides more than almost any other how the pool looks at a glance and how its water stays clean. A skimmer pool holds its water about 15 cm below the surrounding deck, and wall-mounted units sip the surface into the filter from wherever they sit. A deck-level — or overflow — pool holds its water flush with the deck instead, spilling it continuously into a hidden channel that runs the whole perimeter. Same job, two completely different mechanics, and the choice applies to any shape of pool you build.

What doesn't differ is worth naming first. Both systems feed the same filtration loop, need the same turnover — the whole volume of water passing through the filter every 4–6 hours — and take the same heating, lighting and chemistry. Either one can be beautiful, and either one can be badly built. What differs is what sits below the waterline, what that structure costs, exactly how clean the surface stays, and the specific look the water has from a sun lounger.

freeboard — the gap between water and edge — in a skimmer pool versus a deck-level overflow pool: ~15 cm vs ~0 cmfreeboard — the gap between water and edge — in a skimmer pool versus a deck-level overflow pool
wall skimmer units a private pool typically needs, about one per 25 m² of surface: 1–3wall skimmer units a private pool typically needs, about one per 25 m² of surface
typical shell premium the overflow edge adds over an equivalent skimmer pool: +15–30%typical shell premium the overflow edge adds over an equivalent skimmer pool
turnover time both systems share — the edge changes how water collects at the surface, not how fast it's filtered: 4–6 hrsturnover time both systems share — the edge changes how water collects at the surface, not how fast it's filtered

At a glance

	Skimmer	Deck-level overflow
Water level	~15 cm below deck	Flush with the deck
Surface cleaning	Wall skimmers, wind-assisted	Entire perimeter skims continuously
Water quality	Good	Best possible
Look	Classic set-in pool	Mirror sheet in the terrace
Extra structure	None	Perimeter channel + balance tank
Shell cost	Baseline	+15–30%
Best for	Budget-aware family builds	Design-led builds, plunge pools

The physical difference, in one sentence

Freeboard is the technical name for the gap between the water surface and the top of the pool edge, and it's the whole story here. In a skimmer pool that gap is real — about 15 cm — which absorbs the small waves bathers make and stops them slopping onto the terrace, while giving the wall-mounted skimmer openings something to draw from. In a deck-level pool the freeboard collapses to almost nothing: the water sits flush with the coping and spills over continuously.

That spillover doesn't go to waste. It runs into a perimeter channel — finished as a grate or a narrow slot — and down into a balance tank, a buffer reservoir that catches the swing every time someone gets in or out and displaces water, then feeds it back through the same pump and filter a skimmer pool uses. Both systems end up filtering the same water the same way; they only disagree about how it first leaves the surface.

Water quality: why overflow wins on paper

A skimmer pulls from fixed points — one wall unit per roughly 25 m² of surface, placed on the wall the prevailing wind blows toward so the breeze helps deliver debris to it. That works well, but it means dust and pollen on the far side of the pool have to drift across open water before anything catches them, especially on a still day.

An overflow pool skips the drifting entirely: the whole perimeter skims at once, continuously, so nothing has to travel far to leave the surface. That's the real reason many European countries require deck-level or overflow systems on public pools by law. For an ordinary family pool that's covered every night and brushed weekly, a skimmer system's water is still genuinely good — the gap between the two is real but easy to overstate for a backyard nobody photographs for a living.

What overflow costs you in structure

A skimmer pool needs almost nothing beyond the wall boxes themselves, plumbed into the usual loop. An overflow pool needs a perimeter channel running the full edge, a balance tank sized to absorb bather displacement, and a coping ring levelled to within a few millimetres all the way round — because the water has to spill evenly everywhere, not just pool at the lowest point.

That structure, not the visible edge detail, is what typically adds 15–30% to the shell cost of an overflow pool over a skimmer equivalent. It scales with perimeter, which is exactly why the premium is easiest to justify on a small pool — a plunge pool's channel is short, an estate-sized pool's channel is long.

The look: a classic pool, or a mirror in the terrace

A skimmer pool reads as a set-in pool — you can see the edge, the water sits visibly below the surrounding surface, and it's the shape everyone recognises instantly as a swimming pool. It's a classic look for a reason: it's honest about what it is.

A deck-level pool reads differently. With the water flush to the terrace and no visible lip from most angles, it becomes a sheet of water inside the paving — the reflecting-pool effect that photographs so well at dusk with a little lighting. It's also the base a raised infinity edge is built from: one wall turned into an overflow weir toward a view is how most 'infinity' pools are actually built, so choosing overflow now keeps that option open later.

Living with each system

A skimmer pool asks for a small, recurring habit: empty the basket every so often, and before frost, lower the water below the skimmer mouths and blow out the lines so nothing cracks over winter. It's a five-minute job, not a chore.

An overflow pool has no basket to empty — the channel clears itself continuously — but the balance tank and channel want occasional inspection, and the millimetre-precise coping means any settlement in the ground over the years shows immediately as an uneven spill on one side. A skimmer pool shrugs off the same small settlement without anyone noticing.

Choose skimmer if… choose overflow if…

Choose the skimmer system if the pool is first and foremost a family tool, if the budget needs to stay honest, or if your builder is a conventional local outfit who has built a hundred skimmer pools and few of the other kind.

Choose the overflow edge if the pool is small enough that the channel premium stays modest, if it's meant to be looked at as much as swum in, or if a view behind the pool makes a full infinity weir worth the extra structure. Either way, get the choice right before the shell is designed — this is one of the few decisions here that genuinely isn't a later upgrade.

If you're weighing it, put a compact or plunge-sized pool into the free designer under both edge modes and see how differently the same water reads.

Our take

If the pool is a family tool, the skimmer system gives you 90% of the experience for clearly less money. If the pool is part of the architecture — or small enough that the channel premium is modest — the overflow edge is the single upgrade with the biggest visual and water-quality payoff.

Frequently asked questions

Does an overflow pool use more water than a skimmer pool?: No — the water that spills over is caught in the channel and recirculated, not lost. Evaporation runs slightly higher than a covered skimmer pool, mainly because the moving sheet at the edge exposes a bit more surface.
Can I add an overflow edge to an existing skimmer pool later?: Realistically no, not as a simple retrofit. The channel, the balance tank and the millimetre-level coping are structural decisions baked in from the start — treat overflow as a rebuild, not an upgrade, and decide before construction begins.
Is skimmer water actually dirty?: No — it's good, just not quite the best possible. A well-run skimmer pool with a weekly brush and a nightly cover looks perfectly clean to anyone who isn't a pool engineer.
Can a raised pool use either edge system?: Yes — the edge system and the rim height are independent choices. A raised pool can skim from its wall units or overflow at its top edge exactly like an in-ground one.
Which is easier to keep clean day to day?: Overflow, mechanically — nothing sits waiting to be emptied. A skimmer pool asks a few minutes of basket-emptying now and then in exchange for a much simpler structure underneath it.

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