The Best Bilge Pumps for Boats of Every Size
By Lance Greiner — General Manager, Boater's World · Former Platform GM, Travelcamp RV· June 22, 2025· 1 min read· Updated Jul 5, 2025
Lance Greiner is a career marine and automotive retail professional with more than 15 years of dealership management experience. He currently serves as General Manager at Boater's World in Florida, overseeing full mar…
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Every powerboat sinks at the dock at least once in its life, usually because a stuck float switch or a clogged intake screen meant the bilge pump didn't run when it should have. The category is dominated by a handful of brands that all make decent pumps — but installation, switching, and redundancy matter more than the pump itself.
Sizing by Boat Length
| Boat Length | Primary Pump | Secondary Pump |
|---|---|---|
| Under 18 ft | 750 GPH | None required (manual recommended) |
| 18–22 ft | 1100 GPH | 750 GPH high-mount |
| 22–28 ft | 1500 GPH | 1100 GPH high-mount |
| 28–35 ft | 2000 GPH | 1500 GPH high-mount + manual |
| 35+ ft | 3700 GPH | 2000 GPH high-mount + manual |
The Rankings
Built-in non-mercury electronic switch, robust impeller, and a 5-year warranty. The 1500 GPH is the right size for boats 18–25 feet and the integrated switch eliminates the most common failure mode (stuck mechanical float).
| Capacity | 1500 GPH |
| Switch | Built-in electronic |
| Voltage | 12V |
Self-priming, dry-run safe, and pulls down to 1mm of water in the bilge. The Aqua Void's diaphragm design moves less volume than a centrifugal pump but runs dry without burning out — useful for boats stored on trailers.
| Capacity | 1000 GPH |
| Type | Diaphragm |
| Dry run | Safe |
True intelligent switch with current sensing instead of a float. The Gulper IC senses when the impeller is moving water versus air and shuts off automatically — eliminates float switch failures entirely.
| Capacity | Variable |
| Switch | Current-sense |
| Use | Large boats |
If you prefer a separate switch (allows easy replacement), the Ultra Safety Systems Junior is the most reliable mechanical float switch made. Encapsulated, mercury-free, and rated for over 100,000 cycles.
| Type | Mechanical float |
| Mount | Separate |
Every offshore boat needs a manual pump as backup to the electric. The Titan moves 19 gallons per minute by hand and mounts to a bulkhead so a single person can pump while staying low in the boat.
| Type | Manual diaphragm |
| Capacity | 19 GPM by hand |
Switch Choices
Three switch types: mechanical float (cheapest, most failures), electronic field-sense (sees water without moving parts, mid-priced), and current-sense (best, most expensive). For 2026 builds, current-sense or electronic field-sense is the right choice. Mercury float switches are illegal in many jurisdictions and obsolete everywhere.
Two-Pump Strategy
A serious bilge installation uses two pumps: a primary at the deepest point of the bilge handling normal water, and a secondary mounted 4–6 inches higher that only activates if the primary fails or is overwhelmed. The secondary pump is your insurance policy for the day the float on the primary sticks open or a hose ruptures.
Wiring and Maintenance
Wire each pump on its own circuit direct from the battery (through a fuse) so it runs with the main switch off — a boat sinking at the dock with the battery isolator open is the most common failure mode. Test both pumps monthly by lifting the float manually. Clean the intake screens at every haul-out. Replace pumps every 5 years even if they still work.
Top Picks & Comparison
| # | Product | Price | Rating | ||
|---|---|---|---|---|---|
| #1 | |
Rule 1500 GPH Automatic |
$129 | — | View on Amazon |
| #2 | |
Johnson Pump Aqua Void |
$199 | — | View on Amazon |
| #3 | |
Whale Gulper IC |
$329 | — | View on Amazon |
| #4 | |
Ultra Safety Systems Junior |
$99 | — | View on Amazon |
| #5 | |
Whale Titan Manual Pump |
$169 | — | View on Amazon |