To drain a hot tub, turn off the power at the breaker, attach a garden hose to the main drain valve, open it, and let the water run out. One manufacturer, Bullfrog, says its spas drain about 5–10 gallons (20–40 liters) per minute, so a 400-gallon tub takes 40 to 80 minutes. Clean the empty shell and filters, refill through the filter compartment, and only then turn the power back on.
How often to do it is a separate question, covered in how often to change hot tub water. Bullfrog suggests roughly every three to four months and Jacuzzi every 3 to 6 months. Your owner’s manual has the final say.
Before you drain
- Stop adding chemicals. Jacuzzi recommends adding none for at least 24 to 48 hours beforehand, so there is less residue in the water.
- Plan where the water goes. Jacuzzi says to check with your council on where to dispose of spa water. Hot Spring warns that water with a high sanitizer level may harm plants and grass, and Bullfrog says sanitizer must be under 0.5 ppm before you water vegetation with it.
- Keep it away from the house. Bullfrog says to direct the drain away from window wells and basement entrances.
Drain it, step by step
- Cut the power. Jacuzzi says to turn off the power to the spa at the circuit breaker before draining it, and not to turn it back on until the spa has been refilled. Bullfrog says to turn off the main electrical breaker. Hot Spring’s manual says to trip both GFCI breakers in the subpanel.
- Find the drain valve. It is usually behind the equipment door or front panel; the exact spot and cap differ by brand, so use your manual.
- Attach a garden hose and route it to the drain area.
- Open the valve. The spa drains by gravity. Bullfrog’s figure is 5–10 gallons per minute, which means 40–80 minutes for 400 gallons (400 ÷ 10 and 400 ÷ 5). Your tub’s size and hose will change that. If you don’t know its size, see how many gallons a hot tub holds.
- Open the secondary drain if your spa has one. On Hot Spring models it releases about one gallon from the bleed line.
- Mop up the rest. Bullfrog says to use a wet/dry vac for water left at the bottom.
Clean it while it is empty
- Keep the empty shell out of the sun. Bullfrog says an empty spa must not be left exposed to sunlight because shell damage may occur, and Jacuzzi says the same for hot weather. Shade it and refill promptly.
- Clean the shell with the products your manufacturer allows. Bullfrog names mild, diluted dishwashing soap, window cleaner or spa surface cleaners, applied with a soft cloth, and rinsed well.
- Clean the filters. Hot Spring says to clean and rotate the cartridges every time the spa is drained. See hot tub filter cleaning.
Refill and restart
- Close every drain and fill through the filter compartment (Hot Spring). Fill to your manual’s water line: Hot Spring’s is about 1½ inches above the top of the highest jet.
- Mind the water temperature. Hot Spring says refill water should be between 50° and 70°F (10° and 21°C) to avoid high-limit tripping, and that it is not recommended to refill when the air temperature is below 50°F (10°C).
- Turn the power on only after the spa is full and the equipment door is closed.
- Heat-up. Hot Spring says its spa normally reaches 100°F within 18 to 24 hours. Expect other brands to vary.
- Balance the water. Hot Spring says adjusting total alkalinity first is important (see hot tub pH and alkalinity). Then it superchlorinates new water with 1½ teaspoons of sodium dichlor per 250 gallons (950 liters). That dose is that manufacturer’s; use the one in your own manual.
In freezing weather, draining and winterizing takes extra steps; see hot tub water care in winter. For a routine to follow afterwards, see the hot tub and spa care guide.
Sources
- Bullfrog Spas: Draining, Cleaning, and Refilling your Bullfrog Spa
- Jacuzzi (Spaworld Australia): How to drain and refill a Jacuzzi J-400 Collection spa
- Hot Spring Spas: Highlife Collection 2025 Owner’s Manual
Research checked 2026-10-08.
