Closing and Opening a Hot Tub for the Season

The two decisions that matter at the end of a season are whether the tub stays full and whether it stays powered. Everything else follows from those. Get them right and closing takes an afternoon, opening takes an hour, and nothing is damaged in between.

What you cannot do is leave water sitting unattended through a freeze. That is the one outcome worth planning around.

Not sure where your water is? Check your readings.

Deciding: drain, or keep it going

Three workable approaches, and the right one depends on the property rather than the tub.

Drain it

The simplest and safest, and the right answer for a property nobody visits through winter. No water means nothing to freeze, and an empty tub can sit for months without attention.

Keep it heated

If you are using the tub through the season, holding it at temperature is straightforward and the insulation does most of the work. Water in use is water being watched, which is the real safeguard.

Keep it above freezing without using it

The middle option: water stays in, but held above freezing rather than at soaking temperature. On a powered tub, freeze protection handles it automatically. On an unpowered one, a stock tank heater or pond de-icer rated for the volume does the same job.

This only works with reliable power. Plan for an outage separately, because a de-icer without electricity is an ornament.

Closing down

Whichever route you take, the water care part is the same.

1. Let sanitizer fall to zero if the water is going onto ground. Stop dosing and leave the cover off for a day or two, or use a neutralizing agent and retest
2. Let it cool. Very hot water damages roots and soil life, and on a wood fired or hybrid tub the firebox must be completely cold before you drain below the fill line
3. Drain fully, spreading the water rather than putting several hundred gallons on one spot
4. Clean while empty. Soft cloth, mild plant-based cleanser, rinse thoroughly. Pay attention to the waterline. Nothing abrasive, no pressure washing, no vinegar
5. Deal with the filter. Soak it, dry it completely, and store it dry rather than leaving it damp in the housing all winter
6. Dry the interior as far as you reasonably can, and leave nothing standing in fittings
7. Leave the external drain valve open through freezing conditions so nothing is trapped in it
8. Cover it, and check the underside of the cover is dry before it goes on for months

Full detail on the draining half in draining and refilling.

On a powered tub, follow your manufacturer's winterizing instructions for the equipment itself. Water left anywhere in a pump, heater or line is what causes freeze damage, and that part is not a water care question.

Through the closed season

An empty tub asks for very little, but not quite nothing.

• Check the cover after heavy snow, since accumulated weight and trapped moisture are the two things that shorten a cover's life
• Make sure meltwater is not collecting inside and refreezing
• Keep the drain clear
• If wildlife is a consideration, check nothing has moved into the equipment housing

If the tub is staying full and heated at a property you visit occasionally, the check that matters is that the power is still on and the water is still moving. A tub that lost power three weeks ago is a very different problem from one that lost it yesterday.

Opening up

Treat it as a first fill rather than a restart, because that is what it is.

1. Inspect before anything else. Look over the interior, the fittings, the cover and, on a wood fired tub, the firebox and chimney including the spark-arresting cap
2. Clean the interior even if it looked clean when you closed it. Dust, pollen and insects find their way in over months
3. Fit a clean filter, or a fresh one if last season's was near the end of its life
4. Flush the hose before it goes in, particularly if it has been sitting outdoors
5. Fill through a hose filter
6. Balance in order: total alkalinity 80 to 120 ppm first, then pH, then calcium hardness 150 to 250 ppm, then sanitizer last
7. Test two or three times in the first week, since new water moves more than settled water

Test your source rather than assuming it matches last year, especially on a well, where the water table shifts seasonally. More in your water source, and what it means.

Two things people get wrong at opening

Sanitizing straight away on a new or newly-clad cedar tub. If any cedar has been replaced over the winter, expect a short tannin period and keep sanitizer out until the water runs clear. Tannins in the presence of bromine can bond to the tub surface and stain it. More here.

Lighting the fire before the tub is full. Easy to do in the enthusiasm of the first soak of the year. Fill to the line marked on the tub, or at least 4 inches (10 cm) above the chimney collar, and keep it there the whole time the firebox is hot.

If you have an AlumiTub

The structure does not mind being left empty. It holds water because of how it is welded rather than because the wood has swollen, so draining for the winter costs you nothing and there is no re-swelling period in spring.

On an Electric or Hybrid, freeze protection heats the water automatically whenever cold is detected, for as long as there is power, which is what makes leaving it full through winter workable at an unattended property. Plan for a long outage separately, and on a Hybrid the firebox covers exactly that gap.

On a Wood Fired, draining is usually simplest. Never drain below the fill line until the firebox has completely cooled, and leave the external drain valve open through the freeze.

Refill to alkalinity 80 to 120 ppm corrected first, pH 7.4 to 7.8, calcium hardness 150 to 250 ppm, and bromine 2 to 3 ppm and never above 3. Good Clean Living Water Care covers the clean and the refill. For the wider winter picture, cold weather testing and winterizing.

Not sure where your water is? Check your readings.