An outdoor shower is one of those backyard features that feels effortless in July and terrifying in November. The moment temperatures drop below freezing, every ounce of water sitting in your supply lines, shower head, and mixing valve becomes a liability. Water expands roughly nine percent when it freezes, and that expansion exerts pressures exceeding 25,000 pounds per square inch inside a closed pipe. A single overnight freeze can split copper fittings, crack PEX connections, and destroy mixing valves that cost more than a hundred dollars to replace.
The good news is that winterizing an outdoor shower takes less than an hour if you know the steps and do them in the right order. I have been winterizing showers in zone 5 for years — we get weeks of subzero nights — and I have never lost a fitting. The process is straightforward once you understand it. If you are considering an outdoor shower and live in a cold climate, do not let winter maintenance scare you off. It is one of the easiest seasonal tasks in your yard. For broader outdoor shower inspiration and planning, browse our outdoor living guides.
Understanding Why Outdoor Shower Plumbing Is Vulnerable
Indoor plumbing is protected by the thermal envelope of your house. Even in an unheated basement, temperatures rarely drop below 40 degrees Fahrenheit because the surrounding soil and the house above provide insulation. Outdoor shower plumbing has none of that protection. Supply lines run along exterior walls, under decks, or through open air where they are fully exposed to ambient temperatures. A cold, clear night with no wind can drop surface temperatures well below the air temperature due to radiative cooling.
The most vulnerable components are horizontal runs of pipe where water can pool and not drain by gravity. Vertical drops will usually empty themselves if you open a valve at the bottom, but horizontal sections and low spots hold water like traps. Mixing valves, backflow preventers, and shower heads also retain small amounts of water in their internal passages. These are the components that freeze first and fail most often.
PEX tubing is more freeze-tolerant than copper because it can expand slightly before rupturing, but it is not freeze-proof. PEX manufacturers explicitly state that their products should not be left pressurized and full of water in freezing conditions. Copper has zero flexibility — it cracks at the first hard freeze. CPVC, which some older installations use, becomes extremely brittle in cold weather and shatters easily. Regardless of your pipe material, the winterization process is the same: get the water out.
Step 1: Locate and Close Your Shutoff Valve
Every properly installed outdoor shower has a dedicated shutoff valve inside the heated envelope of the house. This valve sits on the supply line between your home's plumbing and the point where the pipe exits through the exterior wall. If your shower has both hot and cold supply, there will be two shutoff valves — one on each line.
The shutoff valve is typically a ball valve (quarter-turn handle) or a gate valve (round wheel handle) located in the basement, crawl space, or utility closet nearest the exterior wall where the shower supply exits. If you did not install the shower yourself, trace the supply lines from the shower head backward through the wall until you find the valves. Label them with a tag or marker if they are not already labeled. You do not want to be searching for them in a dark basement when the first freeze warning hits.
Close both shutoff valves completely. For a ball valve, turn the handle perpendicular to the pipe. For a gate valve, turn the wheel clockwise until it stops. Once the shutoff is closed, no new water can enter the outdoor portion of the plumbing.
If your outdoor shower is a simple garden-hose-connected setup — like our Cedar Single Wall Shower — winterization is much simpler. Disconnect the garden hose, drain it, and bring it inside. Then open the shower valve to let any remaining water drip out. You are done. The steps below apply to hard-plumbed installations with dedicated supply lines.
Step 2: Open All Outdoor Valves and Drain the Lines
With the shutoff valves closed, go outside and open every valve on the shower. Turn on both hot and cold handles fully. If there is a separate diverter or volume control, open that too. You want every valve in the outdoor section wide open so gravity can pull water downward and out.
Water will flow for a few seconds to a minute as the remaining supply in the lines drains. Let it run until it stops completely. If your plumbing has a drain port or petcock at the lowest point of the outdoor piping — and it should — open that as well. This is a small valve, usually brass, installed at the lowest point of the horizontal run specifically for winterization. It allows water that has pooled in low spots to drain out.
Leave all outdoor valves in the open position for the entire winter. This is counterintuitive — you would expect to close everything tightly — but leaving them open serves two purposes. First, it allows any residual moisture to evaporate rather than pooling. Second, if someone accidentally turns the shutoff valve back on during winter, the water will flow out the open outdoor valve rather than sitting in the lines and freezing.
Step 3: Blow Out the Lines With Compressed Air
Gravity draining removes most of the water, but it does not remove all of it. Horizontal sections, slight uphill runs, valve bodies, and the internal passages of mixing valves all retain water. To remove this residual water, you need compressed air.
You do not need an industrial compressor. A standard pancake-style shop compressor set to 50 PSI is sufficient. Do not exceed 80 PSI — higher pressures can damage PEX connections and blow out O-rings in valves. If you do not own a compressor, you can rent one for twenty dollars at most equipment rental shops, or borrow a neighbor's. Some people use a battery-powered tire inflator, but these typically do not have enough volume to clear a full run of plumbing. A shop compressor with at least a 6-gallon tank is ideal.
To blow out the lines, you need a compressor fitting that connects to your plumbing. The easiest approach is to use a blow-out plug — a brass fitting with a male garden hose thread on one end and an air compressor quick-connect on the other. These cost about five dollars at any hardware store. Attach the blow-out plug to the boiler drain or hose bib nearest the shutoff valve on the indoor side, connect your compressor hose, and blow air through the lines.
You will hear air hissing through the open outdoor valves and see water sputtering out. Keep the compressor running for 30 seconds to a minute after the sputtering stops to ensure the lines are clear. Repeat the process for each supply line — hot and cold independently. If you have a mixing valve, switch the outdoor handle between hot and cold while blowing air so the air flows through both internal passages of the valve.
Step 4: Anti-Freeze Options for Extra Insurance
In most situations, draining and blowing out the lines is sufficient. But if your installation has complex plumbing with multiple low spots, long horizontal runs, or components you cannot easily drain — such as an anti-scald valve or backflow preventer — adding non-toxic antifreeze provides an extra margin of safety.
Use only propylene glycol-based antifreeze rated for potable water systems. This is the pink stuff sold as RV antifreeze. Do not use automotive ethylene glycol antifreeze — it is toxic, and you will be flushing this through your drinking water supply lines when you reopen in spring. RV antifreeze protects to minus 50 degrees Fahrenheit and is food-safe.
Pour antifreeze into any component that might hold residual water: the shower head (remove it and pour a small amount into the supply nipple), the mixing valve body (pour through the supply ports), and any low-point drain traps. A pint or two is usually enough for the entire shower. The antifreeze displaces any remaining water and prevents ice formation even if moisture remains in the system.
Label your shower clearly — a simple tag on the shower handle that says "Winterized — Do Not Turn On" prevents guests or family members from accidentally running the system before it has been de-winterized in spring.
Step 5: Protecting Wood Panels and Structures
The plumbing side of winterization gets the most attention, but your shower's wood structure also benefits from cold-weather care. Cedar, which we use in all of our shower designs, is naturally rot-resistant and handles moisture well. But winter presents a specific challenge: standing water that freezes in joints, between slats, and on horizontal surfaces causes ice expansion that can loosen fasteners and open gaps over repeated freeze-thaw cycles.
Start by cleaning the wood before winter sets in. A stiff brush and a bucket of water with a splash of oxygen bleach (sodium percarbonate) removes any mildew, algae, or dirt that accumulated during the shower season. Rinse thoroughly and let the wood dry for at least two days. Do not power wash cedar shower panels — the pressure can tear soft grain and accelerate weathering.
If you applied an exterior wood oil or stain earlier in the year, inspect the finish. A healthy finish will cause water to bead on the surface. If water soaks in immediately, the finish has degraded and a fresh coat before winter provides protection. For unfinished cedar that you intend to let weather naturally to gray, no finish is needed — just the cleaning step.
For the platform base, sweep away leaves and debris that can trap moisture against the wood. If your shower is in a spot that collects drifting snow, brush off heavy accumulations after storms. Snow itself is not harmful, but a dense pack of snow against horizontal surfaces holds moisture against the wood for weeks. Good airflow is the best defense.
If your shower has a fabric curtain, unhook it and store it indoors. Fabric left outdoors through winter traps moisture against the frame and accelerates mildew. If your shower has a door, leave it slightly ajar so air can circulate inside the enclosure. A closed enclosure traps humidity, which condenses on cold surfaces and promotes mildew growth even in winter.
In areas with heavy snowfall or ice storms, consider covering the shower structure with a breathable tarp or purpose-made furniture cover. Use a cover that allows airflow — never wrap the shower tightly in plastic sheeting, which traps condensation and creates the exact damp environment you are trying to prevent. Secure the cover so wind cannot blow it off, but leave the bottom open for air circulation.
Step 6: Spring Startup Checklist
When spring arrives and overnight temperatures are consistently above freezing — not the first warm day in March, but when you are past the last frost date — it is time to bring the shower back online. Work through these steps in order.
First, inspect all visible plumbing connections and fittings for cracks, drips, or signs of frost damage. Look at joints, valve bodies, and anywhere pipe connects to a fitting. Hairline cracks in copper or CPVC may not be visible until the pipe is pressurized, but obvious splits or deformed fittings should be replaced before you turn anything on.
Second, remove the shower head and any aerators or screens. These can clog if antifreeze residue or sediment has settled in them. Set them aside for reinstallation after flushing.
Third, close the outdoor shower valves. You left them open all winter — now close them before pressurizing the lines.
Fourth, slowly open the indoor shutoff valves. Open them a quarter turn at first and listen for any hissing or dripping outside. Walk out and inspect the lines while the system pressurizes slowly. If you hear water escaping, close the shutoff immediately and locate the leak. If everything is quiet, open the shutoffs fully.
Fifth, go outside and open the shower valves one at a time. Run cold water first for a full minute to flush the lines. The water may be discolored or have a slight antifreeze taste — this is normal. Flush until the water runs clear. Then run the hot side for a full minute. Finally, run both together through the mixing valve.
Sixth, reinstall the shower head and any screens you removed. Run the shower for another minute to flush the head and confirm full flow and proper mixing.
Seventh, check the wood structure. Tighten any fasteners that may have loosened over winter. Inspect the base platform for stability. If you covered the shower, remove the cover and store it. Give the wood a quick brush-down if it collected debris or cobwebs.
Your outdoor shower is now ready for the season. The entire spring startup takes about 20 minutes once you have done it a few times.
Winterization Timeline by Climate Zone
The timing of your winterization depends on where you live, and getting it right matters more than any individual step. Winterize too early and you miss weeks of potential shower use in pleasant fall weather. Winterize too late and one unexpected early freeze can damage your plumbing overnight.
In USDA zones 3 and 4, winterize by early to mid October. First freezes can come as early as late September, and hard freezes — below 25 degrees — are common by mid October. Do not gamble on an extended warm spell. In zones 5 and 6, aim for late October to early November. You will typically get a few light frosts before the first hard freeze, giving you a buffer, but do not wait until Thanksgiving. In zone 7, mid to late November is usually safe. Hard freezes are less predictable this far south, so watch the forecast closely. In zone 8, freezes are rare but not impossible. Many zone 8 gardeners never winterize, but if your area gets one or two freezing nights per year, drain the lines on those nights as a precaution.
When in doubt, winterize. The process takes less than an hour and costs nothing. Repairing freeze damage to plumbing costs hundreds of dollars and can take your shower out of commission for weeks while you wait for parts or a plumber.
Common Winterization Mistakes
The most common mistake is assuming that draining alone is sufficient. Gravity draining removes 80 to 90 percent of the water in a well-sloped system, but the remaining 10 to 20 percent sitting in valve bodies, low spots, and horizontal sections is enough to cause damage. Always blow out the lines with compressed air after draining.
The second most common mistake is forgetting about the shower head. Shower heads retain water in their internal chambers and flow restrictors. Remove the shower head for winter or, at minimum, turn it upside down to drain and blow compressed air through it. A frozen shower head will crack its internal housing, and replacement heads for outdoor-rated fixtures are not always cheap.
Another common error is closing the outdoor valves after draining. This traps any residual moisture inside the valve body with no way to evaporate. Leave outdoor valves open all winter. This also serves as a visual reminder that the system is winterized — if you walk outside and see open handles, you know the system is shut down.
Finally, neglecting the backflow preventer. If your installation includes a backflow preventer (required by code in many jurisdictions), it has internal check valves that hold water. These must be drained separately, often by loosening the test port screws on the side of the device. Consult the preventer's manual for the specific winterization procedure.
Frequently Asked Questions
Can I leave my outdoor shower running on a slow drip to prevent freezing instead of winterizing?
The slow-drip method works for indoor faucets on exterior walls because the water is continuously replenished with warm water from inside the house. For outdoor showers, where the entire supply line is exposed to freezing air, a slow drip does not generate enough heat transfer to prevent freezing in sustained cold. Once the air temperature drops below 20 degrees Fahrenheit for more than a few hours, even a steady drip will freeze in an exposed line. It also wastes a significant amount of water over the course of a winter. Proper winterization is more reliable and costs nothing.
What if my outdoor shower does not have a dedicated shutoff valve inside the house?
If your shower is plumbed without a dedicated indoor shutoff, you need to add one before next winter. In the meantime, you can shut off the main water supply to the house, open the outdoor shower valves to drain the lines, and then turn the main supply back on. This is inconvenient and you risk forgetting to do it, but it works as a temporary solution. A plumber can add a ball valve on the outdoor shower supply line in about an hour for around 150 to 200 dollars — well worth the investment.
Is it okay to leave the shower head mounted on the shower during winter?
It depends on the shower head type and your climate. Simple fixed shower heads can be left mounted if you remove them from the supply nipple and turn them upside down to drain completely. Rain-style shower heads with anti-drip mechanisms should be removed because they retain water by design. In zone 5 or colder, I remove the shower head entirely and store it in the garage. It takes 30 seconds to unscrew and prevents a $50 to $150 replacement cost if it cracks.
Do I need to winterize a solar shower bag or camping shower?
No. Solar shower bags and gravity-fed camping showers are designed to be emptied and stored. Just dump the water, let the bag dry with the cap off, and fold it up for indoor storage. There is no plumbing to freeze. This is one of the advantages of simple, portable shower setups — zero winterization hassle.
How do I winterize a shower that has an in-line water heater?
Tankless water heaters used for outdoor showers require their own winterization procedure in addition to the shower line winterization. Most outdoor-rated tankless units have a drain plug on the bottom that allows you to empty the heat exchanger. Consult your heater's manual for the specific steps. Generally, you close the water supply, disconnect the inlet and outlet lines, open the drain plug, and blow compressed air through the heater to clear residual water. Some units have a built-in freeze protection mode that draws a small amount of electricity to keep the heat exchanger warm, but this only protects down to about 15 degrees Fahrenheit and requires a constant electrical connection. For sustained cold climates, manual draining is safer.