Keeping your swim spa’s water fresh and clean is essential for a safe and enjoyable experience. But how often should you change the water in a swim spa?

Recommended water change frequency

Swim spa water should typically be drained and refilled every three to six months. This interval depends on how often you use the spa, how many people use it and how well you maintain the water chemistry.

Why fresh water matters

Over time, a swim spa’s water accumulates dissolved minerals, body oils, sweat and cleaning chemicals. These contaminants make it harder for sanitiser to do its job, allowing bacteria and algae to grow and causing unpleasant odours and cloudy water. Changing the water periodically removes these dissolved solids and refreshes the spa.

Factors that influence water-change schedule

• Usage frequency: The more often you swim or relax in your spa, the more contaminants build up. Heavy use may require water changes every three months, while light use may extend the interval to six months.
• Number of bathers: More people in the spa means more lotions, oils and sweat introduced to the water, accelerating the need for a water change.
• Water chemistry and sanitiser levels: Staying on top of pH, alkalinity and sanitiser levels (chlorine or bromine) helps water last longer. Letting chemical balance slip shortens the water’s usable life.
• Environmental factors: Outdoor spas are exposed to leaves, pollen and airborne contaminants. A well‑fitting cover reduces debris and slows down evaporation.

Maintenance tips between refills

You can keep your swim spa’s water cleaner for longer by practising a few simple maintenance habits:

• Rinse debris such as leaves and insects out of the spa after each session.
• Test pH, alkalinity and sanitiser levels weekly and adjust as needed.
• Clean filters monthly and replace them when worn.
• Shock the water periodically to oxidise contaminants and refresh sanitizer.
• Perform a deep clean and flush plumbing lines every quarter to remove biofilm.

Summary

Most swim spas need a water change every three to six months. How often you drain and refill depends on usage, the number of bathers, water chemistry and environmental conditions. Regular testing, cleaning and using a good cover will help extend the life of your water between refills.

For expert swim spa servicing and water care, book a service with our technicians. If your spa needs repairs, our repairs team can help. When it’s time to upgrade or accessorise, explore our in-stock hot tubs and accessories to get everything you need.