It's not good to leave your pool empty when the weather gets cold. Leaving your pool filled with water can help prevent your vinyl or concrete foundation from being damaged.
Once water is removed (and subsequently, the interior hydrostatic pressure), if there's an influx of groundwater, it will push the pool up and out of place. As a general rule, you shouldn't keep any pool empty for longer than it needs to be. Get the work done that you needed to do and refill it as soon as possible.
An empty swimming pool can pop, or float out of the ground. This is due to possible hydrostatic pressure from unknown underground water.
In-ground pool draining requirements are similar to those of their above-ground counterparts. Drain the water down to no more than 6 inches from the bottom of the skimmer if you plan to use a standard floating winter cover. Use your pool filter, switched to the "Drain" setting, to empty the pool water.
If your pool has outlived its usefulness and it would cost more to repair than you can afford, you can cover it. Building a deck over a pool presents a challenge similar to any raised deck, so be prepared for hard work, sore muscles and a great sense of accomplishment.
Do you need to drain any water when winterizing an above ground pool? The answer hinges on how you protect your skimmer during the winter. If you're concerned about freezing and cracking, and don't use a winter skimmer cover plate, then you should drain the water level below the skimmer and returns.
An uncovered pool will lose water in the winter to evaporation in the same way it does during the summer. But the water loss is only about a quarter-inch on average during a 24-hour period when the pool is not in use. An uncovered or covered pool can have problems in the plumbing lines or pump.
Most experts recommend waiting at least until temperature drops below 65 degrees Fahrenheit (18 degrees Celsius) to winterize your pool. However, if you can wait longer until your pool is below 50 degrees Fahrenheit (10 degrees Celsius), you will have a much lower risk of problems occurring.
If ground water is not a problem a pool can be left empty for weeks or even months as long the hydrostatic relief in the bottom of the pool is open and functioning. If the time frame of the pool being empty gets into freezing weather there is real risk of freeze-thaw damage to surface of the pool.
Modern concrete pools can usually stand being drained for as long as needed, but there'll still be a risk of popping if the ground water level is high. Fibreglass pools are less resilient. The floor may come loose and float to the top when refilled, even after a short period.
An empty pool (or as little as 1/4 filled) and an exposed liner on a hot day can cause the liner to shrink from the heat and deem the liner useless. An empty pool is also susceptible to collapse. Especially, in high winds and/or bad weather.
Closing a pool that is green with algae, or dirty with debris or with water that is unbalanced, leads to heavy staining and saturation of the water with dead algae cells, which makes it easier for subsequent generations to grow.
The weight of ice or snow are common culprits of pool collapse. Draining your pool too much. An older inground pool may not be able to withstand the weight of dirt against it once it is empty or if the water levels are too low. Groundwater can also push against the pool walls and cause it to collapse.
The reason you don't want to completely drain your pool during winter is because the dry, freezing air can cause rips, cracks and tears in your liner. By allowing pool water to cover the liner, you're preventing the liner from drying up and getting damaged.
You can do the “bucket test” on your pool to measure evaporation. Place a bucket of water beside the pool and mark both the water in the bucket and the pool water level. Wait 24 hours then check the loss of both. If the pool loses more water than the bucket, then you have a leak.
Remove any top decking concrete walkways, coping tiles and any other concrete around the pool that you don't want anymore. Toss it into the pool over the holes you have made. Cover the old cement with a layer of crushed rock. Then cover this with a layer of sand, or just fill it up the rest of the way with dirt.
For example if our pool is 30′ long, 20′ wide' and 6′ deep, it has a total volume of 3,600 square feet (30x20x6). The total square footage divided by 27 is 133.33, this indicates that your pool will need 133.33 cubic yards of material to fill it in.
A much less expensive way to reclaim the space your pool is taking up is to simply cover it with a deck. After the pool is emptied and drainage provided, deck builders simply build a deck over the top of it.
A well-maintained swimming pool that does not have any leaks should not have to be drained or refilled every year—even every two or three years.