Where Is the Bilge Pump Located on a Boat?

A bilge pump plays a vital role in a boat and requires routine maintenance to be effective. That said, not many people understand how important a bilge pump is or even what it is to begin with, let alone knowing where is the bilge pump located on a boat.

Some boat owners neglect the bilge pump for too long, resulting in an inefficient boat. Knowing that a bilge pump needs cleaning is one thing; actually conducting routine maintenance is another.

At any dockyard, there is always one boater that has ignored the bilge pump maintenance. If you are reading this, chances are you’re interested in knowing how to locate a bilge pump on a boat and also knowing how it actually works. In that case, you’ve certainly come to the right place.

Where Is the Bilge Pump Located on a Boat

What Exactly Are Bilge Pumps?

The bilge pump is a water pump located at the lowest part of a boat. It is designed to get rid of water that might spill, spray or splash on the boat.

Typically, this section of the boat is covered by a flat floor with the bilge hidden underneath. If a boat didn’t have a bilge pump, it would become flooded because there will be nothing preventing water from accumulating inside the boat.

Since any boat bilge will collect water, the purpose of the bilge pump is to draw the water out. A bilge pump uses suction or pressure to achieve this. For it to function properly, a bilge pump requires regular maintenance. If the bilge pump is not maintained, the bilge water can become polluted.

How Does a Bilge Pump Work?

Automatic bilge pumps work by getting rid of excess water from a boat. Excess water is a result of packing gland drips, rainwater, spray from waves, and more. It is important to note that the aim of a bilge pump is not to prevent a boat from sinking if it takes on water. However, it can be beneficial by helping to buy some time when an emergency occurs.

The bilge pump on a boat should have a 24-gallon per minute pumping capacity at the very least. This is a minimum on boats that are less than 65 feet long. High-quality bilge pumps have a higher rated capacity.

Bilge pumps are generally centrifugal pumps or diaphragm electrical. Centrifugal bilge pumps are designed like a turbine with a rotating impeller. When water gets into the pump, the impeller begins to spin and pushes out the water.

These types of pumps can rapidly pump out a lot of water. But that’s not all. They are also low maintenance. It is important to note that these types of bilge pumps are not self-priming, meaning that they will have to be sitting in water before they begin to pump.

On the other hand, diaphragm pumps pull water in through an intake valve. The water is then pumped via an output valve. These pumps are self-priming, meaning that they can function even if they are dry. They are much better at pumping water out at greater distances.

However, diaphragm bilge pumps have a few drawbacks. First, they do not pump water as fast as centrifugal bilge pumps. Also, these types of pumps are prone to clogging by debris and dirt. The valves on these bilge pumps can clog and cause leaks.

The best option to have on a boat is the centrifugal pump.

Where Is the Bilge Pump Located on a Boat

Where Is the Bilge Pump Located On a Boat?

As stated earlier, a boat’s bilge pump is generally located at the lowest area of the bilge. This location allows it to seamlessly collect and pump out water.

Some boats have a secondary bilge pump that is sometimes located a bit higher. One bilge pump is typically sufficient for a small boat, but it might be necessary to have a supplementary bilge pump for larger boats. There are even some boats with as many as three bilge pumps.

When it comes to efficiency, automatic bilge pumps are a lot more effective than manual ones. That being said, new and inexperienced boat owners tend to overlook their bilge pumps. A bilge pump can be found installed under a boat’s inboard engine compartment. Certain boats don’t even have bilge pumps as they aren’t required by law to be on recreational boats. Nevertheless, if you are considering getting a boat, you should really think about getting a bilge pump. Having an automatic bilge system is essential to protecting your investment.

Difference Between Automatic and Manual Bilge Pumps

It is important to note the difference between a manual bilge pump and an automatic bilge pump.

An automatic bilge pump comes with an inbuilt float switch that detects water levels. The float switch turns the bilge pump on automatically when the need arises. An automatic bilge pump is recommended for boats that are more than 20 feet long, especially a boat that you sleep in. This is because a float switch can be a significant part of boat safety.

Unlike automatic bilge pumps, manual bilge pumps do not have a float switch. Nevertheless, it is possible to integrate a float switch to a manual pump and make it work as an automatic pump.

Bilge Pump Maintenance

Cleaning your bilge pump regularly is extremely important for every type of boat, although quite a lot of boat owners do not bother to do this. Going too long without cleaning your bilge pump could cause the water inside to become polluted. You should also note that even a brand new boat can have a dirty bilge area.

The bilge area could be filled with construction debris such as fiberglass and bits of wood that were leftover from the construction of the boat. All of this has to be properly cleaned out before heading into the water for the first time. It doesn’t make any sense to use the bilge pump while the area is still messy.


Having a reliable and efficient bilge pump is an extremely important yet overlooked aspect of owning and operating a boat. With proper maintenance and cleaning, the bilge pump can protect the boat and ensure that it remains afloat. If a bilge pump fails while you are out in the water, it could put you in quite a lot of danger.

This is why it is crucial to know the steps required to maintain your bilge pump. You can even consider getting a manual bilge pump to supplement the automatic one in case of emergencies. Remember, adequate maintenance is essential to having a bilge pump that functions effectively.

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