Hot Tub Winterization in Tennessee: Run It or Drain It?

Tennessee winters are a tease. Some weeks it's 60°F and you want to soak. The next week there's a hard freeze warning and the wind chill drops to 12. Hot tub owners have a real decision to make: keep the spa running through winter, or fully shut it down? Here's how a tech thinks through it.

The Case for Running It

If you use your spa even occasionally — say, twice a month or more between November and March — keeping it running is almost always the right call. Here's why:

• Convenience. A 40°F night with a hot soak is a real reason people buy hot tubs in the first place.
• Lower failure risk. A spa that's running and at temperature is less likely to have problems than one that sits cold for months. Seals stay lubricated, pumps stay primed, water doesn't sit stagnant.
• Energy cost is manageable. A well-insulated spa in Middle Tennessee adds roughly $30–$60 per month to your electric bill in the coldest part of winter. Less if you keep the cover in good shape.
• Freeze protection is automatic. Modern spa control packs have built-in freeze protection that kicks pumps on when water temperature drops near freezing. The water keeps moving, lines don't freeze.

The Case for Draining It

Draining and winterizing makes sense in a smaller set of circumstances:

• You're traveling for an extended period (a month or more) where you won't be able to check on the spa.
• The spa has known issues — leaks, intermittent error codes, weak heater — that make it likely to fail at the worst possible time.
• You're not going to use it through winter and would rather not pay to heat empty months.
• You're listing the house for sale and don't want to manage the spa during showings.

The risk of fully winterizing is mostly about doing it incorrectly. A spa that wasn't fully drained, with water still sitting in a pump volute or low pipe segment, can split a fitting overnight in a hard freeze. The damage isn't always visible until spring.

How to Keep a Running Spa Safe Through Winter

• Inspect the cover. A waterlogged cover loses insulation value and your spa works much harder. Press on the cover — if it sags or feels heavy, it's saturated and should be replaced.
• Check the freeze-protection setting. Most spas turn pumps on automatically when temps drop. Verify this is enabled in your settings.
• Keep the cabinet sealed. Make sure cabinet doors close fully and aren't damaged. Cold wind blowing across the equipment bay is the #1 cause of frozen plumbing in a running spa.
• Keep an eye on the GFCI. If the breaker trips during a storm and resets to "off," the spa will cool down. Set a phone reminder to check it after every winter storm.
• Maintain water chemistry. Cold water can mask sanitizer needs. Test weekly even in winter, because biofilm doesn't really sleep.

How to Winterize Properly

If you decide to shut down, here's the right sequence:

1. Turn off power at the disconnect.
2. Drain via the main drain valve and a submersible pump if needed.
3. Loosen pump unions and let any trapped water drain out.
4. Use a wet/dry vacuum on each jet face for a few seconds, blowing or vacuuming any standing water out of the lines.
5. Pour a small amount of RV/spa antifreeze into the skimmer, footwell drain, and pump suction to displace residual water. Use spa-rated antifreeze, never automotive.
6. Leave the cover on but cracked slightly for ventilation. Sealed shut on an empty spa, condensation and mildew become the new problem.

Most homeowners would rather not handle steps 4–6 themselves. A typical professional winterization visit takes about an hour and ensures no surprises in February.

While you're thinking about freeze risk on the spa, it's the right week to think about the rest of the house plumbing that freezes in a Nashville cold snap — outdoor spigots, crawl-space supply lines, and any pipes running through unconditioned space. The cold front that splits a hot tub fitting is the same one that splits a hose bib.

Restarting in Spring

• Inspect for any rodent activity in the cabinet (mice love empty winter spas).
• Visually inspect plumbing for any cracks or stress that may have developed.
• Refill, prime the pumps, restore power, and let it heat up before adding chemistry.
• Run a line-cleaning product on the first heat cycle to clear any winter residue from the plumbing.

What We Recommend in Middle Tennessee

For 90% of the Nashville-area homeowners we work with, the right answer is: keep it running, maintain the cover, and skip the winterization. Our winters are mild enough and short enough that the math favors running over shutting down for almost everyone who uses their spa at all. The exception is the seasonal homeowner who's away from November through March — for them, professional winterization is well worth the visit.