Winterizing a hot tub means fully draining the water, clearing every drop from the plumbing lines, cleaning the shell and filters, and securing the cover, in that exact order.
Skip any step and trapped water will freeze, expand, and crack pipes, jets, or the heater. In Colorado mountain communities, the stakes are higher than most guides account for: temperatures at elevation drop below freezing on September nights, and a vacation property tub left with water in the lines after a fall visit is a plumbing repair waiting to happen.
This guide covers the full process, explains where most owners get it wrong, and explains why a professional pool and hot tub maintenance service call in Colorado before winter is worth every dollar.
Should You Winterize or Keep It Running?
Before draining anything, answer one question: will this tub be used consistently through winter, or will it sit unused for weeks at a time?
| Situation | Right call |
|---|---|
| Primary residence, used weekly through winter | Keep running, maintain chemistry, check water level, secure cover |
| Vacation property, unoccupied more than 3 weeks | Winterize, no chemistry monitoring means freeze risk is real |
| Mountain property, overnight temps below 20F regularly | Winterize unless someone is on-site to monitor |
| Rental property with gap between bookings | Winterize between guest seasons |
Running a hot tub through a Colorado winter is fine if the tub is monitored consistently. The problem is an unattended tub at a mountain property. A power outage of 24 to 48 hours in sub-zero temperatures is enough to freeze and crack plumbing even in a well-insulated tub. If nobody will be on-site to check on it, winterize it.
What You Need Before You Start
- Garden hose connected to a drain area that can handle 300 to 500 gallons
- Wet/dry vacuum with a blower function, minimum 5 hp for effective line clearing
- Non-toxic propylene glycol spa antifreeze, required in Colorado, not optional
- Filter cleaning solution
- Spa surface cleaner and non-abrasive cloth
- 2 to 3 hours on a day when temperatures will stay above 40F through the following night
Time the process carefully. Do not begin when overnight lows are already near freezing. Water draining slowly from lines in near-freezing temperatures can freeze mid-process and cause the exact damage you are trying to prevent.
How to Winterize a Hot Tub: Step by Step
Step 1: Turn Off Power at the Breaker
Cut power at the dedicated GFCI breaker before touching anything. Water and live electrical components create serious risk during maintenance. If the tub is hardwired, confirm the breaker is off before proceeding.
Step 2: Drain the Shell
Locate the main drain valve in the equipment access panel. Connect a garden hose and open the valve. A submersible pump speeds the process significantly. Once the bulk of the water is out, use the wet/dry vacuum to pull remaining water from the footwell, pockets sit in low corners and around the jets even when the shell looks empty.
Step 3: Clear the Plumbing Lines
This is the step most DIY winterizations get wrong, and where freeze damage originates. According to the Pool and Hot Tub Alliance, complete water removal from all plumbing, pump housings, and equipment is the single most critical step in hot tub winterization.
Open the equipment access panel. Loosen the unions on each pump and the heater to release water trapped there. Remove the lowest drain plug from the front of each pump. Then switch the wet/dry vacuum to blower mode and push air through every jet opening, the filter cavity, and the blower port if your tub has one. Work each jet individually, 30 seconds of forced air per opening minimum.
In Colorado, where overnight temperatures can swing 40 degrees between a warm afternoon and a cold night, incomplete line clearing is the most common cause of freeze damage on mountain property tubs.
Step 4: Clean and Store the Filters
Remove the filter cartridges. Rinse thoroughly with a garden hose, then soak overnight in filter cleaning solution. If the cartridges have been in service more than 12 months, replace them rather than storing used ones through winter. Store cleaned filters indoors in a dry location, do not leave them in the tub cavity over winter.
Step 5: Clean the Shell
Wipe down the full interior surface with a non-abrasive spa cleaner. Pay attention to the waterline where calcium scale and biofilm accumulate. Colorado hard water leaves visible mineral deposits at the waterline that harden further over a dormant winter season, a scale remover handles this before you close.
Step 6: Add Spa Antifreeze
Non-toxic propylene glycol spa antifreeze is listed as a required step for cold climates by the APSP industry winterization guidelines, the American Pool and Spa Professions trade standard. In Colorado mountain communities at elevations above 7,000 feet, where temperatures regularly reach -10F or colder, skip it at your own risk.
Pour one gallon into the filter cavity and one gallon into the top of each pump after the lines have been blown out. This protects against residual moisture the vacuum did not fully clear. Use only non-toxic propylene glycol-based spa antifreeze. Automotive antifreeze is toxic and will damage equipment.
Step 7: Secure the Cover
Place the cover on the tub and lock it down. In Colorado mountain areas with significant snow loads, check that the cover is in good condition before closing for the season. A compromised cover that collapses under heavy snow damages the shell and creates a cleanup problem in spring. If the cover is cracked, waterlogged, or no longer seals properly, replace it before winterizing.
Where DIY Winterization Goes Wrong
Most hot tub damage blamed on a bad winter is actually incomplete winterization. These are the three points where owners consistently miss:
- Line clearing stopped too early, the shell looks empty but pump housings and jet plumbing still hold water
- Antifreeze skipped because it seemed optional, at elevation above 7,000 feet in Colorado, it is not optional
- Cover condition not checked before closing, a cracked or waterlogged cover that collapses under snow load causes shell damage that costs more than the cover replacement would have
A professional winterization service catches all three. Colorado Pool + Spa Scapes handles full seasonal closings for hot tub and pool owners throughout the Roaring Fork Valley and Vail Valley, drain, line blowout, filter removal, shell clean, antifreeze application, and cover inspection in a single visit. If something looks wrong with the equipment during the process, you know before spring, not after.
Why Colorado Mountain Tubs Need More Than a Standard Winterization
Freeze-thaw cycles are more destructive than sustained cold. A tub that freezes, partially thaws on a warm afternoon, then refreezes overnight puts repeated stress on plumbing fittings that sustained low temperatures do not. This is the standard pattern across Colorado mountain communities from October through March. Complete water removal is the only protection, and it takes the right equipment and the right sequence to do it correctly.
Vacation properties have no margin for error. If you are closing up after a fall visit and will not be back until spring, there is no one to catch a problem if something was missed.
A professional hot tub maintenance visit before you leave costs a fraction of what a cracked manifold or failed pump costs to repair in April.
Pool maintenance and construction planning happen in the same window. Fall is when mountain property owners start planning for next season, whether that is a pool maintenance schedule going into spring opening or early conversations about new pool construction. Colorado Pool + Spa Scapes works across both: seasonal maintenance and service for existing pools and hot tubs, and custom pool and spa construction for mountain resort properties throughout the valley.
Schedule Before the First Cold Snap
If your property needs winterization this season and you want it handled by a team that knows what Colorado water and elevation actually do to equipment, pool and hot tub maintenance in Colorado from Colorado Pool + Spa Scapes is the right call.
Reach out through our contact page to get on the schedule before the first hard freeze.
Frequently Asked Questions
What happens if you do not winterize a hot tub?
Water left in the shell, plumbing lines, pumps, or heater will freeze and expand in cold temperatures. Frozen water cracks PVC pipes, splits jet fittings, and can damage the heater element and pump housing. Repairs from freeze damage typically run several hundred to several thousand dollars depending on what fails. In Colorado mountain climates where overnight lows regularly reach single digits, un-winterized tubs that sit unmonitored through winter rarely come through undamaged.
How long does it take to winterize a hot tub?
Plan for two to three hours for a thorough winterization. The drain itself takes 45 minutes to an hour depending on tub size. Blowing out the lines, cleaning the filters, wiping down the shell, and adding antifreeze account for the rest. Do not rush the line-clearing step, incomplete blowout of the plumbing is the single most common cause of freeze damage on tubs that were technically winterized.
Can you winterize a hot tub yourself?
Yes, if you have a wet/dry vacuum with a blower function and follow the steps in order. The most common DIY mistake is incomplete line clearing, owners drain the shell and assume the job is done, leaving water sitting in pump housings and jet plumbing. If you are not confident in the blowout step, or if the tub is at a property you will not be monitoring, professional winterization is worth the cost compared to a spring repair bill.
When should you winterize a hot tub in Colorado?
Winterize before overnight temperatures consistently drop below freezing in your area. In most Colorado mountain communities, Avon, Glenwood Springs, Steamboat Springs, that window opens in September or October depending on elevation. Do not wait for the first hard freeze. Winterizing in near-freezing conditions creates its own risk of water freezing mid-drain in the plumbing lines.