Drainage is one the most important factors in the life expectancy of an above ground pool. Simply put, drainage is how well the area around your pool drains surface water away from the pool. When it rains, does your yard flood with water that sits above the surface and does not drain through your soil or run away from your yard? This is an example of a drainage issue. Sitting water can flood the limestone and sand base under your above ground pool, slowly eroding this base material away. In addition to erosion, sitting water can accelerate rusting on the frame of metal pools. Over time this can greatly weaken your pool and lead to a potential collapse.
The most critical period for drainage issues in relation to above ground pools is the late spring. With melting snow and heavy rains, yards are often inundated with water during this period of the year. The danger in this situation is two-fold. Excessive rain can cause erosion and rusting, while a cold spring can see temperatures bounce from freeze to thaw constantly. This freezing can cause sitting water to expand and cause your pool to heave under the frost. The pressure of the frost pushing upwards can crumple your pool wall and cause extreme damage and possible collapse.
With all the possible situations which can arrive from improper drainage, how can a pool owner protect their investment and ensure proper drainage around their pool area? In most circumstances, grading the area away from your pool and placing clear/drainage stone around the pool is more than enough. Water will always run downhill, so the simplest form of drainage is to slope the land around your pool away from the pool itself. A rock border placed 1.5 feet around the perimeter will also stop water from saturating the soil around the pool and causing erosion.
However, this solution will not work for every situation. When a pool must be installed in an extremely sloped area, the higher grade of the yard around the pool will cause water to run from the yard into the pool area. In such a circumstance, a French drain will be required to divert water away from the pool. A French drain is system that contains a perforated pipe buried in gravel, contained with a filter fabric wrap. Similar systems are used around houses to stop basements from becoming flooded. Water will pass through the top layer of grass, through the filter fabric and gravel, then into the pipe. The pressure of the accumulating water will push the water down the pipe and away from the pool, exiting in the lower grade away from the pool. This will keep your pool area dry and safe from erosion, frost heave, and other water related problem. Although they can be very expensive, retaining walls can also greatly improve the drainage situation around a pool built near/into a slope. Retaining walls can divert the flow of water coming downhill, and keep backfill pressure off of your pool wall.
If you are thinking of getting an above ground pool installed, ask your contractor what their recommendations are for the drainage of your specific situation. Drainage is critical to the longevity of your pool, and can vary region to region based on soil type.