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How to Winterize a Pontoon Boat? – 6 Steps to Remember

Fact checked by William Hart

how to winterize a pontoon boat

Is winter approaching your city? Are you looking for ways to protect your pontoon against treacherous weather? Here, we provide an ultimate guide on how to winterize a pontoon boat for new owners.

This process aims to remove all water from the vessel, purify the gasoline, change the oil and oil filter, and run antifreeze and fogging oil through the engines to prevent water from becoming frozen.

Failing to properly winterize results in severe damage when you de winterize the vessel in the spring. So, scroll down for our expert guide!

Table of Contents

Step-by-step to Winterize a Pontoon Boat


What to prepare

Before storing a pontoon boat outside, gather the following tools and materials to winterize it:

  • Boat soap
  • Boat polisher
  • Antifreeze
  • Fogging oil
  • Engine oil and oil filter
  • A soft bristle brush
  • A pressure washer or a garden hose with a nozzle
  • Absorbent towels
  • Winter storage covers

Step 1. Clean the boat’s interior and exterior


Winterizing pontoon boats begin with cleaning them thoroughly. You don’t want the clinging mud, algae, and grime to dry and harden on the boat’s hull, making it more laborious to clean when the next season begins.

You should run your pressure washer over the entire boat. Then, use a deck brush to scrub off any stains on the hull and pontoon tubes. Finally, rinse off the soap and use a towel to wipe off the remaining water.

Now, proceed to clean the interior and storage compartments. You should remove the fishing equipment, carpets, skis, electronic equipment (such as depth finders), life jackets, wakeboards, and flotation devices from the boat. Then, clean them and store them separately.

In addition, check out online pontoon organization ideas and tidy up your boat inside. When items are left aboard messily, they will gather moisture and facilitate the growth of mold and mildew during winter.

When the hull and deck are completely dry, apply a boat polish. The product will restore the sheen of the boat paint and protect it from dust and sunlight.

Step 2. Stabilize the fuel


When fuel sits for a prolonged period, its ingredient separates and accumulates in the gas tank’s bottom. A fuel stabilizer will get rid of this problem. All you have to do is pour the correct amount directly into the gas tank.

How much to use depends on the manufacturer; some products require 1 ounce for every gas gallon, while another can treat 16 gallons with the same amount.

Note: We recommend keeping your fuel tank level at around ¾ filled to full. Doing so will reduce the air inside the gas tank. Air can trap moisture, freeze in cold temperatures, and drop into the fuel during winter.

Step 3. Add antifreeze and fogging oil to the engine


Damage from water freezes can cost boat owners thousands of dollars. So, remove any water in the engine block and add antifreeze to avoid the problem.

  • Inboard/outboard vessels: You should drain the water in the cooling system and pour propylene glycol based antifreeze into the engine compartment. Then, hook a motor flusher into the boat’s water intake before turning on the engine to circulate the antifreeze.
  • Inboard vessels: You should drain the coolant and place one end of the raw water intake hose into a container filled with antifreeze (avoid ethylene glycol base products, which are not eco-friendly). After that, start the engine.
  • Outboard engines: You need a boat winterizing kit to run antifreeze through an outboard engine. Start by draining the coolant water, then fill the tank of the winterizing kit with antifreeze and hook the kit to the flushing muffs. Finally, turn on the valve and start the engine.

As the engine is running and circulating the antifreeze, you should spray fogging oil into the carburetor and spark plug holes.

Step 4. Change the engine oil and oil filters

Changing the oil before storing a vessel can minimize oil impurities and accumulations when the boat is not in use, so don’t forget to put the task in your winterizing a pontoon boat checklist.

You will need to locate the oil fill cap, remove it, and pump out the old oil. Then, twist to detach the old filter and replace it with a new one. Finally, fill the oil compartment with fresh oil.

Step 5. Lubricate the grease points and remove the battery

Read the owner’s manual for specific instructions on the control cables’ position and identify their grease points. You need to clean them with a cloth and lubricate them.

In addition, don’t leave the battery onboard during winterization! As your boat sits unattended for a prolonged period, electrical incidents might occur and cause severe damage.

You should remove the batteries, charge them, and store them in a cool and ventilated area. Since batteries drain even when not in use, you might want to charge them a few more times during the off season.

Step 6. Cover the pontoon


There are many winter storage ideas for pontoon boats: trailering them to the garage, using boat lifts and storing them above the water, letting them sit in the water, and stacking them in temperature-controlled facilities.

But no matter if you are storing aluminum boat outside or indoors, shrink wrap a pontoon boat before covering it. Shrink wrapping will guard the boat against wind, moisture, snow, and salt water. You can check Pinterest for the best pontoon wrap ideas.

Pay attention to the tarp you choose to cover a pontoon boat for winter. If you store your vessel indoors, a regular tarp is sufficient. But if you place it outdoors, choose a high-quality boat cover that can repel water efficiently. Snow and rain can pool inside and collapse the toughest materials.

If you leave a pontoon boat in the water in the winter, consider installing pontoon tip protectors. They will safeguard the vessel’s exterior when the wind pumps it against the dock, other pontoon boats in the marina, or other obstructions.



Do you have to winterize pontoon?

You only need to winterize your pontoon boat if the temperatures in your area might drop below 32 °F. You don’t want coolant or remaining water in the pumping system to expand and crack its containers.

How much does it cost to winterize a pontoon boat?

If you hire a service to winterize your boat, expect the following maintenance costs:

  • Cleaning the boat: $10 to $50 per foot
  • Draining the engine, changing oil, and fogging the engine: $200 to $500
  • Stabilizing the fuel system: up to $250
  • Draining other water systems (e.g., exhaust ports, holding tank, bathroom, and pipes running to the kitchen): up to $200
  • Draining and cleaning the live well: $70 to $120

However, if you winterize your boat by yourself, it will cost only about $250. Plus, you can keep the remaining products to use next year.

Tips for leaving pontoon in the water

Storing your boat at marinas during the winter is more convenient if you don’t own a boat trailer, but marine conditions can be harsh on your vessel. Keep these basic tips in mind for storing a pontoon in the water:

  • Check the weather forecast and make sure your boat won’t stand against extreme conditions
  • Paint the boat’s bottom to prevent algae, mud, and other debris build up during the off season
  • Charge the batteries frequently to keep the bilge pump functioning
  • Protect your boat with a specific pontoon cover designed for outdoor use
  • Visit the dock and inspect your boat regularly during winter


Within six steps on how to winterize a pontoon boat, you can sleep safe and sound knowing that your vessel is out of harm’s way. So, don’t procrastinate! Before the temperatures dip, ensure that your investment is fully protected.

You can use this procedure to winterize Bennington pontoon boat and many pontoon models. If you have a problem along the way, don’t hesitate to contact us. We will reply promptly!

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