How to Properly Store Your Boat for the Off-Season

Use this checklist as an overview. The exact process will depend on your boat, engine and local climate. Always consult the owner’s manuals for your boat and its individual systems before getting started.

• Choose an indoor, covered or uncovered storage location.

• Remove personal belongings, food and moisture-sensitive gear.

• Clean and dry the cabin, compartments and upholstery.

• Wash and inspect the hull, deck, propeller and exterior hardware.

• Drain and winterize freshwater, sanitation and raw-water systems.

• Service the engine according to the manufacturer’s instructions.

• Treat the fuel and replace applicable filters.

• Charge, disconnect and properly store or maintain the battery.

• Cover the boat securely while allowing adequate ventilation.

• Check the boat periodically for moisture, pests or cover damage.

When preparing your boat for off-season storage, one of the most important decisions is choosing the right storage option. The type of boat storage you select will determine how much protection the boat receives from weather, sunlight and debris.

Indoor Storage

Indoor storage offers the highest level of protection for your boat during the off-season, shielding it from rain, snow, wind UV rays and debris. If you want extra protection for your boat, a climate-controlled unit can help limit exposure to extreme temperatures and humidity fluctuations, though it’s not always necessary.

Regardless of whether the space is climate-controlled, be sure to drain and prepare the engine, plumbing and other water-containing systems according to the manufacturers’ instructions.

Covered and Uncovered Outdoor Parking Spaces

A covered outdoor parking space provides some protection from the elements and debris while remaining easily accessible, should you need to check up on your boat during the off-season. An uncovered outdoor parking space leaves your boat exposed to weather-related damage, but it’s usually the cheapest option.

Regardless of whether you choose a covered or uncovered parking space, it’s best to use a properly fitted, weather-resistant boat cover that can protect your boat from snow, ice and UV rays, without trapping moisture. Be sure to secure the cover carefully, provide ventilation and check it periodically for pooling water, tears or loose straps. Avoid relying on a basic tarp for long-term protection, because an improperly secured tarp can trap condensation or rub against the boat’s finish.

Tip: Before selecting any storage space, measure the full length, width and height of the boat while it’s on its trailer. You should also confirm the facility’s access rules, clearance limits and documentation requirements.

Before cleaning your boat, remove food, trash and personal belongings — anything that might attract pests or develop smells. You should also take out moisture-sensitive items like electronics, life jackets, fishing equipment, bedding and removable cushions, and check any cabinets, lockers and other compartments to make sure they’re empty.

Once you’ve decluttered and tossed items you won’t need, you can:

• Clean the floors, upholstery and interior surfaces using products approved for your boat’s materials. 

• Defrost the refrigerator and freezer.

• Drain the bilge. 

• Allow everything to dry completely. Leave interior doors and compartments open for a bit of airflow.

Next, clean and inspect the exterior:

• Rinse the hull, deck and topsides with fresh water and a marine-safe cleaner.

• Remove salt, algae and other marine growth before it hardens.

• Check the hull for cracks, blisters, gouges or loose fittings.

• Inspect the propeller, shaft, rudder, trim tabs and through-hull fittings.

• Apply marine wax or another approved protectant to suitable surfaces.

• Inspect the trailer tires, bearings, winch, lights and safety chains.

Remember, it’s important to address leaks or damage before storage when possible, since small problems can compound over time, especially when your boat is sitting unused.

Water left in a boat’s plumbing can freeze and expand, potentially damaging tanks, pumps, hoses and fittings. Even if you live in a mild climate, it’s still important to drain the system to help prevent stagnant water, odors and buildup.

Follow the instructions for your boat’s specific plumbing layout. In general, you’ll need to:

• Pump out and flush sanitation tanks at an approved marine pump-out station.

• Drain the freshwater tank, water heater and connected fixtures.

• Bypass the water heater before adding antifreeze.

• Remove water filters and drain sinks, showers, toilets, livewells and washdown systems.

• Circulate nontoxic marine/RV antifreeze through the plumbing if required.

While all engines need to be drained, cleaned and refilled, engine winterization varies significantly by boat, so it’s important to always consult the owner’s manual before starting. If you’re not sure about any step, it’s never a bad idea to have the work completed by a qualified marine technician.

Most engines require some combination of the following:

• Flush the cooling system with fresh water.

• Drain water from the engine and cooling passages.

• Change the engine oil, oil filter and gear lubricant as recommended.

• Inspect belts, hoses, clamps, seals and other components for wear.

• Lubricate moving parts and protect internal components from corrosion.

• Inspect the propeller and shaft for damage, fishing line or debris.

• Store the engine or drive in the manufacturer-recommended position.

Outboard, inboard and sterndrive engines have different cooling and drainage procedures. Some engines require fogging oil or antifreeze, while others use a different storage process. Don’t assume that one winterization method works for every motor!

The same goes for fuel-storage guidance. Some manufacturers will tell you to keep the tank nearly full, while others will tell you to drain it. Follow the instructions for your specific boat and engine. If you’re going to keep fuel in the tank, add a compatible marine fuel stabilizer in the correct amount and circulate it through the system as directed. Don’t forget to replace applicable fuel filters or water separators, and inspect the tank, lines and connections for leaks.

A battery can gradually lose its charge while your boat is in storage. Inspect the case, cables and terminals for corrosion or damage, then fully charge the battery using a compatible charger.

Depending on the battery type and manufacturer’s instructions, either disconnect it or remove it and store it upright in a cool, dry, well-ventilated location. If you’re disconnecting the cables, remove the negative cable first and reconnect it last.

Use an automatic battery maintainer or check and recharge the battery every now and then. Avoid using an unregulated trickle charger, which may overcharge your battery. Lithium and lead-acid batteries have different temperature and charging requirements, so always pay attention to the battery manufacturer’s instructions.

Tip: If you’re keeping your boat in a self-storage facility, ask about its battery-storage and electrical-use policies before bringing in a loose battery or connecting a charger.

Once the boat is clean, dry and winterized, the last step is to protect it with a properly fitted, weather-resistant cover. Support the cover so rain and snow can’t collect in low spots, and secure it without putting unnecessary pressure on the windshield, railings or other components.

The cover should also allow for airflow. If the cover is sealed too tightly, it can trap condensation, leading to mold, mildew, corrosion or other problems. If you have your boat professionally shrink-wrapped, make sure the wrap includes adequate support and ventilation. 

We recommend checking your boat periodically during the off-season, and especially after severe weather events. Look for pooled water, snow accumulation, torn material, loose straps, pests and excess moisture. If you’re storing your boat in a trailer, check the tire pressure and make sure the wheel chocks and supports haven’t shifted.

Properly winterizing your boat only takes a weekend out of your schedule, but will save you lots of time, expense and labor when it's time to recommission your watercraft in the spring. 

With the right preparation and occasional check-ins, your boat can stay protected throughout the off-season and be ready for your next trip on the water. Use our Storage Locator to find a SmartStop facility near you, and explore our boat storage options to learn more about indoor, covered and uncovered storage at select locations.

When should I prepare my boat for off-season storage?

Prepare the boat as soon as your boating season ends, especially if freezing temperatures are possible. Leaving water, dirt or untreated fuel in the boat for an extended period may increase the risk of corrosion, mold and mechanical problems.

Does a boat need to be winterized if it is stored indoors?

It may. Indoor storage protects the boat from direct weather exposure, but an unheated building can still reach freezing temperatures. Even in a heated space, the boat and its systems should be prepared according to the manufacturers’ storage instructions.

Is covered boat storage better than uncovered storage?

Covered storage provides additional protection from direct sunlight, rain, snow and debris. Uncovered storage is suitable when the boat is fully winterized, properly covered and checked periodically throughout the storage period.

Should I leave the boat’s compartments open during storage?

After cleaning and drying the interior, leaving cabinets, lockers and interior hatches open can improve airflow and help prevent trapped moisture. Exterior openings should remain protected against rain and pests.

Can I use a tarp to cover my boat for the winter?

A tarp can provide temporary protection, but a fitted marine cover is generally better if you’re storing your boat for an extended period of time. Whatever cover you use should be tightly secured, adequately supported so water doesn’t pool and ventilated to minimize condensation.

How often should I check a stored boat?

Check it every month or so, and after severe weather, if possible. Look for cover damage, pooled water, moisture, pests, tire pressure loss and signs that straps or supports have shifted.