How to drain and refill a hot tub, step by step

• Run a biofilm or line flush product if you use one; Master Spas says to use it before draining. See biofilm and line flushing.
• Let sanitizer fall. Bullfrog says water going onto plants should read under 0.5 ppm chlorine or bromine.
• Pick a day above freezing. Master Spas warns that water left in the plumbing can freeze fast.

1. Turn off power at the breaker, every breaker if the tub has more than one circuit.
2. Find the drain valve. Hot Spring's sits below the front panel; on Master Spas models it is behind the front skirt.
3. Attach a garden hose and run it somewhere the water can go, away from the foundation and basement window wells.
4. Open the valve and let it drain by gravity. A submersible pump speeds it up.
5. Open any secondary drain your manual lists. Hot Spring's holds about a gallon from the bleed lines.

Scrub every surface; CDC's hot tub guidance says to scrub thoroughly each time a tub is drained. Clean or replace the filters, and Hot Spring says to rotate them each time. Use a non-abrasive spa surface cleaner and rinse well; Master Spas lists surface cleaners among the causes of foam. See how to clean a hot tub.

1. Close the drain valves and refit the caps.
2. Fill through the filter compartment with a hose pre-filter on the end.
3. Use tap water, never pool water, and no more than 50% softened water.
4. Fill to the level your manual shows, above the jets and below the pillows on Jacuzzi models.
5. Restore power and run the jets. If they sputter, purge the air lock as your manual describes.
6. Balance and sanitize the new water: see hot tub start-up.

Hot Spring doesn't recommend refilling when the air is below 50°F.