Pool glossary

A domed or channeled drain cover that breaks suction vortices, preventing hair or limbs from being trapped at the main drain.

A buffer reservoir that overflow and infinity pools need: it receives the water spilling over the edge and feeds the pump, absorbing the level swings caused by swimmers.

A gently sloping, zero-depth entry that starts at deck level and descends like a natural shore — no steps at all.

A filter using pleated cartridges instead of sand: finer filtration, no backwash water waste, but cartridges need periodic rinsing and replacement.

The standard pool sanitizer: it oxidizes organic matter and keeps bacteria and algae from growing.

The ring of finished stone or masonry that caps the pool wall at the waterline — the edge your hand grabs and your eye reads as the pool's outline.

A powerful jet that produces an adjustable current to swim against — endless swimming in place, even in a 5-metre pool.

A recess at one end of the pool — under a bench, behind a wall or below the deck — housing the roller of an automatic slatted cover.

An edge system where the water stands flush with the surrounding deck and continuously spills into a hidden perimeter channel, from which it is filtered and returned.

The deepest zone of the pool, typically 1.8–2.0 m in family pools — deep enough for free swimming and treading water.

Digging the hole the pool sits in — the shell's shape plus working room around it, and the slope from the shallow end down to the deep end already in the ground.

A one-piece factory-molded basin craned into a prepared excavation — the fastest route from order to swimming.

The vertical distance between the water surface and the top of the pool edge — typically ~15 cm in skimmer pools, near zero in deck-level overflow pools.

Concrete sprayed at high velocity onto a rebar cage, forming a monolithic shell of any shape — the technique behind most custom concrete pools.

A one-way valve in the pool floor that lets groundwater into the empty basin instead of letting it lift the shell out of the ground.

A vanishing-edge wall lowered to a precise weir so water sheets over it into a catch basin below, visually merging the pool surface with the landscape behind.

A long, narrow pool built for exercise swimming — typically 12–25 m long, 2.5–4 m wide, uniformly ~1.35 m deep.

A suction point at the pool's deepest point that pulls water from the bottom into the filter circuit and makes full draining possible.

Small-format tile (2–5 cm) mounted on mesh sheets — the format that wraps curves, radii and Roman steps without cutting.

The perimeter channel of a deck-level pool that catches the continuously overflowing water — finished as a grate or a narrow slot.

A modular deck element — porcelain, concrete or natural stone — laid on a bed or pedestals around the pool.

The acidity measure of pool water; the target band is 7.2–7.4, where sanitizers work best and eyes and skin stay comfortable.

A small, usually uniformly deep pool (up to ~13 m²) built for immersion rather than swimming — cooling off, soaking, cold plunges.

The paved area surrounding the pool — the room the pool lives in. Slip resistance, barefoot-friendly surface temperature and drainage away from the pool are its three duties.

The joint filler between pool tiles — in pools always a water-resistant epoxy or high-grade cementitious grout that survives permanent immersion and chemicals.

An air-source machine that moves heat from outdoor air into pool water at 4–6× the efficiency of direct electric heating.

A stainless-steel entry that takes no swim space: two rails over the coping and rungs down into the water, usually at the deep end.

Sealed LED fixtures set into the pool wall about 50 cm below the waterline, wired through conduits cast into the shell.

A waterproof PVC membrane fitted over the pool structure — the budget-friendly waterproofing and finish in one layer.

A seamless cementitious interior finish (marcite, quartz or polished aggregate) troweled over the shell.

An autonomous electric cleaner that drives the floor (and walls, on better models), scrubbing and filtering into its own canister.

The structural basin of the pool — reinforced concrete, sprayed gunite, factory fiberglass or panel construction — that carries water and ground pressure.

Fully vitrified ceramic tile with near-zero water absorption — frost-proof, colorfast and chemically inert, the most durable pool interior.

The nozzle that pushes filtered water back into the pool, angled to set up a slow rotation that carries debris toward the skimmers.

Semicircular steps flowing out of the pool wall in concentric arcs — the classical entry borrowed from Roman baths.

An electrolysis cell that generates chlorine on site from mildly salty water (~0.4% — a tenth of seawater).

The classic pool filter: water passes through a bed of sand (or glass media) that traps particles, cleaned by backwashing.

The standing-depth zone of the pool, typically 1.0–1.2 m — where children play, adults wade and steps arrive.

A deliberate short-term overdose of sanitizer that oxidizes contaminants after heavy use, storms or the first signs of algae.

A wall-mounted unit that draws the top few centimetres of pool water into the filtration circuit, harvesting floating debris, dust and oils before they sink.

An automatic cover of rigid PVC or polycarbonate slats that rolls out over the water at the push of a button, from a pit or bench.

A floating bubble-foil blanket that warms the water a few degrees and, more importantly, stops evaporation — the pool's biggest heat loss.

A compact heated basin (4–6 m) with a powerful counter-current for swimming in place, often doubling as a hot tub.

A large flat shelf 10–40 cm below the surface — usually 15 cm — sized for in-water loungers, toddlers and lounging.

A porous natural limestone in warm cream-to-walnut tones — the classic Mediterranean coping and deck stone.

The time the circulation system needs to pass the pool's entire volume through the filter once — typically 4–6 hours for private pools.

The band of tile at the water's surface where scale, sunscreen and grime concentrate — tiled even in otherwise plastered pools because tile scrubs clean.

Preparing a pool for freezing weather: lowering the water below the skimmers, blowing out pipes, adding winter chemicals and covering.