Hot tub winterizing: how to close a hot tub for winter

To winterize a hot tub, flush the lines, turn off the breaker, drain the tub, blow the water out of every jet and line with a wet/dry vacuum, open the pump drain plugs and unions, remove the filter, dry the shell, and lock the cover on. If you will be around to use it or check it, the safer choice is to skip winterizing and keep the tub running.

Winterize or keep it running?

	Keep it running	Winterize
Best when	You use it in winter, or someone can check it weekly	Vacant home, seasonal cabin, long absence, no power
Freeze risk	Low. Heater and freeze protection do the work.	Low if done fully. High if any water is left in the lines.
Cost	Winter electricity	Your time or a service fee, plus refill in spring
Main danger	A power cut or fault while nobody is watching	Trapped water freezing in pumps, heater, or fittings

Most freeze damage comes from a half-done winterization or from a running tub that tripped its breaker while the owners were away. If you keep it running, lower the set temperature, keep the cover latched, and have someone look at it during cold snaps.

What you need

• Line flush product
• Garden hose or submersible pump
• Wet/dry shop vacuum that can blow as well as suck
• Towels and a sponge
• Propylene glycol antifreeze (RV or pool type), optional
• Cover straps or locks

How to winterize, step by step

1. Flush the plumbing. Add a line flush product and circulate it per the label. Put the tub away clean. See hot tub line flush.
2. Turn off power at the breaker. Leave it off for the season. Tape a note on the breaker so nobody powers up an empty tub.
3. Drain the tub. Use the drain spigot or a pump. Steps are in how to drain a hot tub.
4. Remove the filter. Clean it, dry it, and store it indoors.
5. Drain the air blower, if the tub has one. Many makers have you run the blower for 15 to 30 seconds on an empty tub to push water out of the air channels. Follow your owner's manual for this step, because it is the only one that involves restoring power briefly with the heater disabled.
6. Open the equipment bay. With the power off, loosen the unions on each pump and the heater so water runs out. Remove the drain plug from each pump's wet end. Put the plugs in a bag and tie it to the pump.
7. Blow out every jet. Set the vacuum to blow. Hold the hose tight against each jet face for 10 to 15 seconds, one jet at a time, until no more mist comes out of the other jets. Open all diverter valves and air controls first. Do the filter housing, suction fittings, and waterfall or neck jets too.
8. Vacuum what is left. Switch to suction and pull water from each jet, the footwell, the filter well, and the drain.
9. Add antifreeze, if you choose to. Pour propylene glycol antifreeze into the filter housing and jets per the product label. It protects any pockets you missed.
10. Dry the shell with towels. Leave the drain valve open so melted snow or rain cannot collect in the lines.
11. Cover and secure. Latch the cover and add wind straps. In heavy snow areas, a sheet of plywood over the cover spreads the load.

Antifreeze: what is safe

• Use only propylene glycol antifreeze sold for RV, marine, or pool plumbing.
• Never use automotive antifreeze (ethylene glycol). It is poisonous and hard to rinse out.
• In spring, flush it out: fill, circulate, drain, and refill. It will foam on the first fill.

Where freeze damage happens

Water expands about 9% when it freezes. The parts that crack are the ones that hold water after a simple drain:

• Pump wet ends (the volute housing)
• The heater tube and its unions
• Manifolds and low runs of pipe under the seats
• Check valves and diverter valves
• Jet bodies

That is why the blow-out step matters more than the draining.

If the tub loses power in a freeze

If a running tub goes dead in winter, do not drain it in a panic. A full, covered tub holds heat for a day or more. Keep the cover shut. Put a small space heater or a work light in the equipment bay, clear of anything flammable and plugged into a GFCI outlet, to keep the pumps and heater above freezing while you sort out the fault. If the breaker is the issue, see hot tub tripping breaker.

Reopening in spring

1. Reinstall the pump drain plugs and tighten all unions by hand. Check the o-rings.
2. Close the drain valve.
3. Install a clean filter.
4. Fill through the filter compartment, then follow hot tub startup after draining.
5. Check the equipment bay for drips once the pumps are running.

Hiring it out

If you do not have a blower vacuum or the tub sits at a property you rarely visit, a professional winterization is worth the money. You can request quotes from local hot tub pros.