How To Clean A Boat Bilge

Paul Stockdale Author Avatar
Written by Paul Stockdale | March 18, 2023
Boat bilge cleaning

Having a dirty boat bilge can cause foul odors and a build-up of oily, dirty water and sludge.

The bilge and bilge pump are important to always keep clean and free from any dirt.

To clean a boat bilge:

  1. Get a biodegradable bilge cleaner
  2. Pour the bilge cleaner into the bilge and let it soak
  3. Scrub the bilge with a brush
  4. Rinse the bilge & drain it out

Over time, the bilge can build up with large amounts of dirt so it should be cleaned regularly.

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1. Get A Biodegradable Bilge Cleaner

The first step in cleaning a boat bilge is to get a biodegradable marine bilge cleaner.

Most retailers price 1-gallon bilge cleaners under $40.

A 1-gallon bilge cleaner is enough to cover cleaning the bilge in the majority of recreational boats.

A biodegradable bilge cleaner can be used on fiberglass, metal, plastic and rubber which are the most common surfaces found inside a bilge.

The benefits of using a biodegradable cleaner to clean the bilge are:

  • Will not harm the surfaces inside a bilge: The fiberglass, rubber hoses, wiring, metal or plastic surfaces will not be damaged when using a biodegradable bilge cleaner
  • Easy to use: Using a biodegradable bilge cleaner is easy to use. Just simply pour it in and let it soak before rinsing
  • Won't pollute the water: A biodegradable bilge cleaner is environmentally friendly and will not harm or pollute the water when used
  • Less acidic than traditional cleaners: A biodegradable bilge cleaner has a less acidic formula than traditional bilge cleaners meaning the bilge area is less likely to get damaged with a biodegradable cleaner
Get a 1-gallon biodegradable bilge cleaner to help safely clean the bilge area.

2. Pour The Bilge Cleaner Into The Bilge And Let It Soak

The second step in cleaning a boat bilge is to pour the bilge cleaner into the bilge and let it soak.

When pouring the bilge cleaner into the boat's bilge, follow the steps:

  1. Ensure there is no fuel or oil in the bilge area. If there is, remove the oil or fuel first with an absorbent pad before pouring the bilge cleaner in
  2. Pour the cleaner over all the surfaces inside the bilge area
  3. Use 1 quarter of a 1-gallon bilge cleaner bottle for every 25' of boat length
  4. Add a small amount of freshwater to the bilge area if it's completely dry
  5. Once the bilge cleaner is poured into the bilge area, let it sit and soak for a minimum of 1 hour while running the boat
  6. The longer the bilge cleaner sits and soaks in the bilge tank, the better the cleaning results will be

The benefits of letting the bilge cleaner soak in the bilge area are:

  • Dissolves & eliminates dirt & grease: Letting the bilge cleaner sit in the bilge tank will help dissolve all the nasty dirt and grime buildup in the bilge area and ensures every piece of trapped dirt is tackled
  • Helps remove foul odors: Letting a bilge cleaner soak in the bilge area will help remove the foul odors that can sometimes form in the bilge area
  • Makes it easier to scrub: Letting the bilge cleaner sit in the bilge tank will make it easier when scrubbing the surfaces inside the bilge area

As stated, the bilge cleaner should be sitting and soaking in the bilge area for at least 1 hour.

Pour the bilge cleaner into the bilge area and let it soak for a minimum of 1 hour.

3. Scrub The Bilge Area With A Brush

The third step in cleaning the boat bilge is to scrub the bilge with a brush or an abrasive cloth.

To scrub the bilge area:

  1. Use a brush and scrub the entire bilge area with it
  2. Scrub the bilge walls in a circular motion to help get those deep dirt stains and grime
  3. Keep hard scrubbing until the entire bilge area has been scrubbed
  4. Ensure the dirt has been removed from every nook and cranny

A brush will help clean those hard-to-reach areas inside the bilge. The dirt and grime should easily break away as the cleaner dissolved it

The benefits of scrubbing the bilge area are:

  • Loosens sludge, grime and grease: Scrubbing the boat bilge will remove all the trapped dirt and sludge with ease
  • Unclogs the bilge pump: Scrubbing the entire bilge area will help to unclog any dirt buildup in the bilge pump
  • Removes the final stubborn dirt: Scrubbing will remove the most stubborn dirt that is stuck on the bilge area walls

Scrubbing the entire bilge area with a brush should take between 15 and 20 minutes to complete.

Scrub the bilge with a brush to remove dirt, sludge, scum and grease.

4. Rinse The Bilge And Drain It Out

The fourth step in cleaning the boat bilge is to rinse it and drain it out.

To rinse and drain out the boat bilge:

  1. Use a hose with fresh water to rinse the bilge
  2. Use as little water as possible to rinse the soapy dirty water from the bilge area
  3. Open the drain and let the dirty water drop into a sealable bucket or container
  4. Alternatively, use a bucket and a sponge to drain the bilge by scooping up the dirty water into a bucket
  5. Keep draining until the entire bilge is dry and empty

When draining the bilge of the soapy and dirty water, ensure that you use a large enough sealable bucket or container to store all the waste.

The benefits of rinsing the bilge and draining it out are:

  • It clears out the bilge: Rinsing and draining the bilge will clear out all the dirt and soapy water
  • It removes bad smells: Rinsing and draining the bilge helps remove the bad smells that may have formed in the bilge area

Rinsing and draining out the boat's bilge should take between 15 to 20 minutes to complete.

When draining the bilge, it is important to be aware of potential oil spills.

If oil spills out onto the ground, use an oil absorbent pad to soak up the oil immediately.

Rinse the boat bilge with fresh water and drain it out completely into a sealable bucket or container.

Products To Use When Cleaning Boat Bilge

The products to use when cleaning a boat's bilge are:

  • Biodegradable bilge cleaner: A biodegradable bilge cleaner will help clean the bilge area
  • Brush: A brush is needed for scrubbing the bilge
  • Sealable bucket or container: A bucket or container is needed for draining the bilge of dirt and dirty water

Products To Avoid When Cleaning Boat Bilge

When cleaning out a boat's bilge, the products to avoid:

  • Power washer: The pressure from the power washer can cause damage to the boat's bilge. This can damage the material and spray toxic oils and grease everywhere
  • Household cleaners: These cleaners are not marine-grade and tend to not be biodegradable. The household cleaners may harm the bilge area
  • Bleach: Bleach can harm the bilge material and pollute the water if it leaks out. Avoid using bleach when cleaning the bilge

Alternative Bilge Cleaning Options

The other ways to clean a boat bilge include:

  • Hire a bilge cleaning company: This service will do all the cleaning work. This will cost $150 on average
  • Hire a professional individual: Hire a person from craigslist or from a local marina to do the cleaning

These options are best for those that want to outsource the cleaning work.

Hiring a commercial bilge cleaning service means cleaning should run smoothly and saves the hassle of doing it yourself.

Frequently Asked Questions About Cleaning A Boat's Bilge

Below are frequently asked questions about boat bilge cleaning.

How Often Should A Boat Bilge Be Cleaned?

A boat bilge should be cleaned once per month.

How Much Does It Cost To Clean A Boat Bilge?

The cost to clean a boat bilge is approximately $50. This is the cost for a bilge cleaner, a sealable bucket for draining and a brush for scrubbing.