Above-ground pools compared

Above-ground pools come in three basic designs. Quick-up pools (also called easy-set or fast-set pools) have an inflatable ring around the top edge that rises with the water as you fill the pool. They are cheap and set up in an hour, but less rigid. Frame pools sit in a frame of steel tubes that holds the liner. They are sturdier, available in many shapes and can still be assembled with few or no tools. Steel-wall pools consist of a corrugated steel wall with an inner liner and are the most robust option for several years in the same spot.

The right size depends on space, use and budget. Pools 3 to 3.66 m in diameter and 76 cm high are the classic choice for families with young children. If you want to swim a few strokes, look at rectangular pools from 4 m long or round pools from 4.5 m. Allow at least half a metre to a metre of space around the pool for the ladder, pump and maintenance.

Remember the weight: every centimetre of water depth adds 10 kg per square metre. A pool 3.66 m across and 76 cm high holds around 6,500 litres – roughly 6.5 tonnes that must stand on perfectly level, load-bearing ground.

The most common mistake with above-ground pools is uneven ground. Even a slope of a few centimetres spreads the water load unevenly – in the worst case a frame buckles or the liner tears. Remove turf, stones and roots, compact and level the ground using a spirit level, and lay a protective ground fleece or mats underneath. Don't put the pool directly under trees, as leaves and blossom quickly dirty the water.

In Germany, whether a pool needs a permit is governed by the building codes of the individual federal states. In many states, pools up to a certain volume – often 100 cubic metres – are exempt from permits, as long as they are not in undeveloped outlying areas. Typical above-ground pools are well below that. Roofs, in-ground pools or pools close to a property boundary can, however, trigger separate rules. If in doubt, ask your local building authority.