Bilge Pump System Maintenance Tips

A leak on a boat is no joke, and if one springs on you, the only thing that’ll keep your vessel afloat is your bilge pump system. 

Bilge pump system maintenance tips

Keeping your bilge pump and its corresponding parts in good working order could save your boat, your equipment, and even your life. A well-maintained bilge pump will have a longer lifespan, which can save you on costly repairs and replacements over time. Follow these maintenance tips to ensure your boat has a long-lasting and efficient bilge pump system.

What is the Bilge Pump System?

The bilge pump system on your boat serves two purposes: To remove nuisance water from within the hull, and to provide protection against flooding and sinking in an emergency situation.

Boat bilge pump system maintenance

The system consists of an electric pump situated in the bilge that feeds a discharge pipe leading to a point above the waterline. Bilge pumps usually have some form of screen on the pump’s inlet port or hose to prevent harmful debris from being sucked into the pump and clogging or damaging it. They also have a thru-hull fitting where the discharge pipe exits the boat. Many bilge pump systems also feature non-return or check valves that prevent water from draining back into the bilge.

Tsunami bilge pump system

Johnson Pump bilge pump system

Some bilge pump systems incorporate two separate bilge pumps:

  • A low capacity pump for getting rid of the nuisance water
  • A high capacity emergency pump to get rid of flooding water in the event of a hull breach 

Boats with more than one bilge compartment have a nuisance water bilge pump for each compartment, or a network of bilge pump intake hoses leading to each compartment. They may also have more than one emergency bilge pump, depending on how large the vessel is.

Fishing boat bilge pump system

Bilge Pump System Maintenance Tips

Check that the bilge pump actually pumps water out by turning the pump on and looking to see if water is flowing from the discharge outlet. If necessary, pour a few gallons of water into the bilge to give the pump something to pump out. Never assume a bilge pump is functioning properly just because you hear its motor running when you switch it on.

Johnson Pump Proline bilge pump

Jabsco diaphragm bilge pump

If the pump’s inlet screen or screen box gets blocked by debris, it’ll prevent water from flowing through the pump. This will cause the pump to overheat and fail. If the inlet screen is damaged, replace it so it doesn’t let any debris enter the pump.

Inspect the discharge hose or pipe for kinks or splits that can prevent bilge water from being pumped out of the boat. Make sure all pipes and hoses are in good condition and aren’t crimped or crushed by other objects.

Test that the float switch is working properly and starts the pump when raised. If your bilge pump has a float switch housed in a screen box, clean the screen box to ensure water can reach the float and activate the switch.

Attwood bilge pump float switch

Rule bilge pump and float switch

Ensure thru-hull fittings and valves work properly and are free of debris. If your bilge pump system has non-return or check valves built in, inspect them for clogs or corrosion. Inspect the thru-hull discharge point to make sure it isn’t blocked.

Check that the fuses protecting the bilge pumps have the correct ratings. If the fuse ratings are too high, they might fail if the pump becomes clogged with debris and the pump motor itself will burn out.

Inspect the batteries and the electrical system, including the wiring between the batteries and the bilge pump, which are prone to corrosion. Replace them if water has penetrated their insulation.

Boat bilge pump water draining

Make sure all connectors, connections and terminals are clean, free of corrosion and secure. Coat any exposed metal connectors with grease.

Inspect the pump’s impeller for wear, broken blades or other damage. The impeller should spin freely and without any resistance when turned by hand. Replacing an impeller should be done once a year anyway, but change it out immediately if it’s damaged.  

Finally, inspect the bilge pump’s diaphragm and valves for any signs of damage, and check that the rubberized diaphragm is still flexible and free of rips or tears. Inspecting the valves and diaphragm should be done at least once every couple of years.

Boat bilge pump maintenance tips

Don't Ignore Your Boat's Bilge Pump System

Keeping up with these bilge pump maintenance tips should help ensure your boat's bilge pump system works properly for years to come. It's one of those areas you should never overlook, for safety reasons above all else. Take good care of your bilge pump system, and it'll take good care of you!



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