In-Ground Pools
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.
Pool lining can dry out when it's left without water overtime. When it dries out, it can expand and stretch, leading to cracks and imperfections. Then, when you fill the pool back up, the water can seep through those cracks and cause damage.
How long can you leave a pool empty? Well, the minimum amount of time possible in order to minimize the risk of serious damage. Most issues that require a pool drain will take at least a day or two to resolve, but it's recommended to not let it sit empty for any extended period of time.
Close the pool for winter – but don't drain it.
In winter, the water in your pool is still your friend. Especially when properly winterized, it helps to protect the pool liner, keep it clean and prevent unnecessary damage from debris, harsh weather and other factors.
Why water level is important
You should never drain your inground pool during winter. Although it may seem scary to leave water in a pool during freezing temperatures, you can actually damage your pool more by removing too much water. Your water should only be drained so it sits just below the skimmer and jets.
It is very important to evaluate the water level in your pool and keep your water level well below the coping and tile or otherwise when the water freezes it will expand and the force of the ice will crack tile and coping resulting in expensive repairs.
The best way to keep your winter cover on your pool is simply to maintain 2 inches of water on top of it and keep it free of leaves and other debris and monitor the water level inside the pool regularly.
Overflowing water can damage the pool wall structure by corroding and weakening the walls of the pool. The water can cause also cause decks to rot and patios to sink around the pool. Another concern from overflowing water is ice damage, which can cause: Cracked skimmers.
If draining is on the agenda, lower the water to a point slightly below the skimmer. Cover the water with the pool cover completely and weigh down the edges of the cover with sand-filled plastic bottles, to keep it in place.
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.
Swimming pool antifreeze, also called non-toxic antifreeze, is the same stuff that RV owners can use in their motor home water systems. For swimming pool use, it can protect swimming pool pipes down to -40°, when added in correct proportion. Here's some Q&A regarding the use of pool plumbing antifreeze.
Drains and Skimmer
The main drain is the primary way that water is drawn from your pool into the pump and filter. The main drain is located on the bottom of the pool in the deepest part. Most pools have one, but larger pools may have multiple main drains. Main drains must be protected by an approved cover.
Because the main drain is not tied into the skimmer in this set-up, pool systems using this configuration usually also have a separate valve to control a separate main drain line that runs from the pool to the pump.
The main drain for a pool is a suction port that should be located at the deepest point on the pool floor. A main drain is responsible for aiding in the circulation and filtration of the pool water. Having a properly working and dedicated main drain line can also allow you to fully drain your pool if necessary.
You don't need to drain your pool, as there is no risk to your pool by it being full. The only thing you lose with a pool filled to the rim is your skimmer's surface cleaning action. Overall, it still draws water and the equipment is just fine.
If your poor overflows, you will need to shock the pool with chlorine, then re-adjust your pH and chemical levels over the next week by continually re-checking the pool's pH with a pool test kit. If the pool was contaminated with debris or dirty water, you will have to clean or replace your filter.
Though the growth rate of algae slows down as water gets colder, we recommend keeping the free chlorine level between 2-4 ppm, as mentioned above. In some areas it's possible to see steady temperatures above 60 degrees in January or even February, giving algae a chance to grow. Don't risk it.