Decide first: run it or close it

You have two good options. You can run the tub all winter, or you can drain it and shut it down until spring. Both approaches work in Indiana. The trouble starts when a tub ends up in the middle, with half the water drained, or full and unpowered.

Running it suits people who will actually use the tub. A spa in good shape holds its temperature well through winter if the cover is sound, and its freeze protection will protect it as long as it has power and a working heater. You will pay more to run it, and you will want to check on it regularly.

Closing it suits people who will not soak for three or four months, or whose tub has a known equipment problem. A tub that is drained and blown out properly cannot freeze, because there is no water left in it to freeze. It costs nothing to run, and it comes back in spring with fresh water.

If you keep it running

Start in autumn with a few checks. Replace a tired filter. Test the water and balance it. Look at the cover: a cover that has taken on water is heavy, poor at insulating, and likely to fail at the hinge. Make sure the foam is dry. If you can, clear the snow from the cover after a storm rather than letting it sit.

Set the temperature where you normally keep it. Do not turn the tub down to save energy during a cold spell, because letting the water cool makes the heater work harder to recover and leaves you with less margin if something goes wrong. Keep the water level above the skimmer so the pump never runs dry.

Check the tub every few days even if you are not using it. A glance at the display tells you whether it is holding temperature. A walk around the cabinet tells you whether anything is dripping. Keep a path to the tub clear, and keep the breaker panel and disconnect accessible.

What to do if the power goes out in freezing weather

This is the situation that damages tubs. When the power fails, the heater stops and the pumps stop, which means the water in the plumbing is no longer circulating or being warmed.

A full tub with a good cover holds its heat for a good while, since a large body of water cools slowly. The risk lies in the narrow lines and equipment where water sits still and loses heat faster. How long you have depends on the temperature, wind, cover and tub, and we cannot give you a reliable number.

Keep the cover on and latched. Do not open it to check. Every time you do, you lose heat.
Know your timeline. If the outage is expected to last a day or more and the temperature is well below freezing, plan to drain the tub rather than hoping.
Drain from the bottom up. Open the drain valve, remove the filters, and open the drain plugs or unions at the pump and heater if you can reach them.
Blow out the lines if possible. A shop vacuum set to blow, a wet-dry vac, or a small compressor at a low setting can push most of the water out of the jets and plumbing.
Insulate the equipment bay as a last resort, with blankets or foam, if you cannot drain.
Do not use a heater inside the cabinet as an improvised fix. It is a fire risk.

If power returns before you have drained, check the tub carefully before restarting it. Look for ice, listen for the pump, and watch the display. If the water level has dropped or you see damage, shut it down and call.

How to winterize properly

Here is the sequence we follow when we close a tub for the season.

Turn off the power at the breaker. Never drain or work in the equipment bay with the power on.
Clean it first. A flush with plumbing cleaner before draining takes out the film that otherwise sits in the lines all winter.
Drain the tub. Use the drain valve and a submersible pump to take out the last of it. Wipe the shell dry with towels.
Remove the filters. Clean them and store them somewhere dry indoors.
Open the unions at the pump and the heater so trapped water can run out.
Blow out the lines. Use compressed air or a shop vacuum in blower mode through the jets and suction fittings, zone by zone, until they stop producing water. Go slowly with air pressure, since plumbing is not built for high pressure.
Dry the equipment bay and look for moisture around the pack.
Close it up. Put the cover on and secure it. A dry tub with a damp cover grows mold, so allow some airflow if you can.

Some owners add a non-toxic antifreeze made for potable systems to the lines after blowing them out. That is a personal decision. Check your tub's manual first, never use automotive antifreeze, and plan on flushing everything thoroughly in spring.

Signs of freeze damage

Freeze damage can be silent. Ice cracks the plumbing, then melts, and the tub looks fine until it is refilled. Watch for these:

Water on the ground or in the cabinet after a cold stretch.
A pump that runs but moves no water, or that sounds different.
A cracked housing, filter canister or union.
A water level that falls after a cold snap.
Jets that no longer work in one section.

Do not restart a tub you suspect was frozen. Running a pump with a cracked housing can pull in air, damage the motor, or spray water over the electrical pack. A technician can test it safely. Our freeze damage repair page explains what that involves.

Spring startup

When the weather settles, start up the tub in an orderly way:

Inspect the shell, cover and cabinet. Look for cracks and pest damage.
Reconnect the unions and check the drain valve is closed.
Install clean filters.
Fill the tub using a hose through the filter compartment to reduce air in the lines.
Bring the power on and prime the pumps. Check each jet.
Walk around the tub and look for leaks while it is running and again an hour later.
Test and balance the water before anyone gets in.

Spring leaks usually show up at this point. If you find one, read about our leak detection service.

When to call for help

You can handle most of this yourself. If a tub will not heat, if the pump sounds wrong, if you suspect a freeze, or if you would rather have someone else do the blowout, get in touch. We would rather hear from you in October than in February.

Winterizing a Hot Tub in Indiana