Replace pool filter sand every five years.

Unless you notice problems sooner — cloudy water that won’t clear, low pressure on the gauge even after backwashing, or sand that feels clumpy when you touch it. Those are the signs it’s time.

Sand doesn’t exactly “wear out.” It gets coated with oils and minerals over time, which makes it stop trapping dirt effectively. Channeling happens too — water starts cutting tunnels through the sand instead of filtering evenly. That’s when pressure drops and debris sneaks back into the pool.

Five years is the safe interval. You can push it to seven if your water is clean and you maintain chemistry well, but I wouldn’t gamble. A sand change costs about $50 and takes an hour. A green pool costs more in chemicals and frustration.

Don’t wait for the algae party.