First-time pool owners often wonder about how often they need to change the water in their pool. But they needn’t worry. In most swimming pools, the water is continually being replaced by the pump system.

Your swimming pool’s pump is working all the time to remove a little bit of old pool water and replenish it with fresh water from your home water supply. Over time, all of the pool’s water will be exchanged for fresh, keeping it safe, clean, and clear for you and your family.

Draining the Pool

When your pump is running, a small percentage of your pool’s water is replaced every hour. But on rare occasions, 100% of the water must be removed and replaced entirely.

This typically occurs when there is major contamination of your pool water, such as from a chemical spill, flooding, or the introduction of human waste into the pool. In order to keep swimmers safe, when these types of catastrophic events introduce a large quantity of contaminants into the water at once, it’s often required that the entire pool be drained, the walls and floor thoroughly cleaned, and all the pool refilled with fresh water.

Chemical Purity

While your pump replaces a small percentage of water continually, the chemicals introduced into the pool water help keep the water that remains in the pool clean and safe for swimmers. Chemicals like chlorine and others kill bacteria and other organisms that can be harmful to swimmers. Direct sunlight also helps keep pool water clear and clean.

Pool technicians also will balance the pH levels of the pool water so that it is neither too acidic nor too base for swimmers. Physical contaminants like leaves and insects are removed by the use of nets and vacuums.

So how often do you need to replace your pool water? All the time!