When Should You Actually Winterize?
Late September is exactly when smart hot tub owners start planning, not necessarily draining yet, but getting ready. The rule isn’t a calendar date, it’s the thermometer: begin winterizing prep once overnight lows are consistently dipping below 50°F and stay alert for the first hard freeze forecast in your area. Wait too long in a cold-winter climate and you risk frozen plumbing, cracked pipes, and a repair bill that dwarfs whatever you’d have spent keeping the tub running through winter instead.
This guide walks through the full process step by step, whether you’re fully shutting down for the season or simply want a seasonal maintenance refresh before the temperature drops. We’ll also cover the increasingly popular alternative: keeping your hot tub running through winter instead of draining it, and what that actually costs.
Should You Winterize at All? Two Paths Forward
Before draining anything, decide which path fits your climate and habits:
Path 1: Keep It Running All Winter (recommended)
Modern hot tubs with full-foam insulation are built to run year-round, even in freezing climates, and many owners find winter is actually the best season to use a hot tub with steam rising off the water on a snowy night is part of the appeal. If you plan to use it regularly (at least weekly), running it through winter is usually more practical than winterizing and can cost as little as $1–$2 per day in electricity, though cold climates can push that 50–100% higher. See our full breakdown of winter hot tub running costs before deciding.
Path 2: Full Winterization and Shutdown
If you won’t use the tub for an extended stretch, you’re leaving town, or you’re decommissioning an old unit, a full winterize-and-drain protects your equipment from freeze damage (if done properly) and saves on electricity during months of non-use. This is the process most owners mean when they ask “how do I winterize my hot tub.”
What You’ll Need
- A wet/dry shop vacuum and/or air compressor
- A garden hose (for draining, if your model doesn’t have a gravity drain)
- A non-abrasive cleaning cloth and mild spa surface cleaner
- Filter cleaner (and a spare filter, ideally)
- Optional: non-toxic RV/plumbing antifreeze for extreme-freeze climates
- A well-fitted, insulated spa cover, plus a cover cap or tie-downs
Step-by-Step: How to Winterize a Hot Tub
Step 1: Balance and Clean the Water Before Draining
It sounds counterintuitive to treat water you’re about to dump, but starting the drain with clean, balanced water reduces the risk of bacteria and biofilm lingering in the plumbing over winter. Run a quick shock treatment a day or two before draining.
Step 2: Turn Off Power at the Breaker
Always disconnect power at the GFCI breaker before opening panels, disconnecting hoses, or draining but never work on the electrical or plumbing system with the unit live.
Step 3: Drain the Spa
Most hot tubs have a drain spigot near the base; connect a garden hose and let gravity do the work, or use a submersible pump to speed things up. Choose a day with above-freezing temperatures for this step so water doesn’t freeze mid-drain.
Step 4: Remove and Clean the Filters
Take out cartridge filters, rinse thoroughly with a filter cleaner, and let them dry completely before storing them somewhere dry and out of direct sunlight. Cracked or heavily worn filters should be replaced now rather than in spring.
Step 5: Blow Out the Lines
This is the step most DIYers skip, and it’s the one that causes the most expensive winter damage. Use a an air compressor or wet/dry shop vacuum on the blow-out setting at each jet, working through every seat and jet body, to force residual water out of the plumbing. Any water left sitting in the lines can freeze, expand, and crack pipes, fittings, or the heater manifold. You can also remove the unions on the jet pumps and blow out the water than might be in the impeller.
Step 6: Clean the Shell and Cover
Wipe down the shell with a non-abrasive spa surface cleaner (never household glass or bathroom cleaners, which can damage acrylic and foam pillows). Clean and condition the cover, and inspect it for water intrusion, tears, or a broken vapor barrier. A compromised cover is one of the top causes of winter freeze damage.
Step 7: Add Antifreeze (Extreme Climates Only)
In regions with sustained sub-freezing temperatures, non-toxic RV/plumbing antifreeze (never automotive antifreeze) can be added to low points in the plumbing as extra insurance. Check your owner’s manual, since not all manufacturers recommend this step for every model.
Step 8: Secure the Cover
A snug, insulated cover with working tie-downs keeps out snow, debris, and moisture, and protects whatever residual insulation value the shell still has during a dormant season.
Winterizing Checklist
| Step | Task | Why It Matters |
|---|---|---|
| 1 | Balance & shock water | Prevents bacteria growth in dormant plumbing |
| 2 | Power off at breaker | Safety before any drain or plumbing work |
| 3 | Drain the spa | Removes standing water that could freeze |
| 4 | Clean & dry filters | Prevents mold, prepares for spring startup |
| 5 | Blow out all jet lines | #1 defense against cracked pipes and fittings |
| 6 | Clean shell & cover | Protects surfaces, catches cover damage early |
| 7 | Add antifreeze (if needed) | Extra insurance in extreme-freeze climates |
| 8 | Secure the cover | Keeps moisture and debris out all season |
Common Winterizing Mistakes
- Skipping the blow-out step. This causes the majority of freeze-related repair calls every spring.
- Draining on a freezing day. Water can freeze mid-drain, trapping ice in the plumbing. Pick a milder day.
- Storing filters wet. Leads to mold and a ruined filter by spring.
- Using the wrong antifreeze. Automotive antifreeze is toxic and should never go anywhere near your spa plumbing — use only non-toxic RV/marine-grade product, and only if your manufacturer recommends it.
- An ill-fitting or damaged cover. Snow load and moisture intrusion are common causes of winter cover failure and, indirectly, freeze damage.
Cost Comparison: Winterize vs. Keep Running
| Full Winterize & Drain | Run All Winter | |
|---|---|---|
| Electricity cost (Dec–Feb) | ~$0 (unit off) | $75 – $450 depending on climate |
| Freeze damage risk | Low, if done correctly | Very low (unit stays warm) |
| Spring startup effort | Full refill, balance, and startup cycle | None — ready to use immediately |
| Usability during winter | None | Full use, including snow soaking |
DIY vs. Hiring a Pro: What It Actually Costs
A DIY winterization costs essentially nothing beyond materials you may already own like a shop vacuum, filter cleaner, and maybe a jug of non-toxic antifreeze, generally under $50 all in. Hiring a spa service company to do it runs $150 to $250 in most markets, sometimes bundled with a broader end-of-season inspection covering the heater, pump seals, and cover condition. For owners who are mechanically comfortable and have an hour or two free, DIY is the more common route, and it’s genuinely not difficult once you’ve done it once. For older tubs with known plumbing quirks, multiple pump systems, or a history of leaks, paying a professional the first time and watching how they do it is a reasonable way to learn the process for future years.
Climate-Specific Considerations
How aggressively you need to winterize depends heavily on where you live:
- Mild climates (Southeast, Pacific coast, Southwest): Many owners skip winterizing entirely and simply keep the spa running, since freeze risk is minimal and running cost stays modest year-round.
- Moderate climates (Mid-Atlantic, parts of the Midwest): A full winterize is common for owners who won’t use the tub regularly, since occasional hard freezes are still a real risk.
- Severe-winter climates (Northern Midwest, Mountain West, Northeast, Canada): Owners either run the spa continuously all winter (the more popular choice, since a well-insulated tub handles sub-zero air temperatures fine) or winterize thoroughly with antifreeze as extra insurance, since a single missed pocket of water in the plumbing can crack a manifold in a hard freeze.
If you’re unsure which category your area falls into this year, check NOAA’s seasonal outlook before deciding, since winter severity can vary significantly year to year even within the same region.
Spring Reopening: A Quick Preview
When it’s time to bring your hot tub back online, the process essentially reverses: reconnect and inspect plumbing, replace or reinstall filters, refill, balance chemistry, and allow the water to reach temperature before use. We cover the full startup process, including chemical dosing order, in our companion guide to spring hot tub startup.
Troubleshooting: Signs Your Hot Tub Wasn’t Winterized Correctly
Even careful owners occasionally miss a step. Watch for these warning signs when you reopen in spring, and address them before refilling:
- Visible cracks in exposed PVC fittings — usually a sign trapped water froze and expanded somewhere in the line.
- A musty or sour smell from the equipment bay — often mold or mildew from moisture left in the cabinet, filter compartment, or a cover with a compromised vapor barrier.
- A heater that won’t fire on startup — sometimes caused by an air lock from incomplete draining, sometimes a sign of a genuinely damaged heating element.
- Pump making a grinding or dry-running noise on first start — shut it off immediately; this usually means the pump is trying to run without adequate water flow and can burn out a seal in seconds.
If you spot any of these, it’s worth a call to a certified spa technician before running the system, since a small plumbing crack that goes unnoticed can turn into a much larger leak once the system is pressurized again.
A Note on Chemical Storage Over Winter
Don’t forget the chemicals themselves. Bromine, chlorine, and pH adjusters should be stored in a cool, dry place away from direct sunlight and away from any flammable materials. A garage shelf works better than a shed that swings through wide temperature extremes. Check expiration dates before spring; most spa chemicals lose potency after 1–2 years, and starting the season with degraded sanitizer is a common cause of stubbornly cloudy water at startup. If you run into clarity issues once you refill, our guide to fixing cloudy hot tub water walks through the most common causes.
Bottom Line
Winterizing isn’t complicated, but it is unforgiving of shortcuts. The jet blow-out step alone prevents the vast majority of costly spring repair calls. Whether you decide to fully shut down for the season or keep your spa running through the cold months, doing it deliberately now, before the first freeze, is what separates an easy spring startup from an expensive one. For help deciding whether your specific model and climate make more sense to run through winter, check our guide to hot tub winter running costs, and browse our full maintenance checklist to keep your spa in top shape year-round.
For more information on how to shop and compare hot tubs before purchasing please visit our hot tub buyer’s guide pages. You can also click on the pink boxes at the top right of every page to get a free local quotes from dealers in your area. Or, click our “Spa Buyer’s Consult” link above to get one-on-one expert advice on how to shop around for the best hot tubs available in your area.
