A high-flow marine pump that is easy on the batteries for its 5 GPM. It is the most expensive pump here.
Amazon $359.09The Shurflo Aqua King II Supreme 5.0 is the better RV water pump overall, rated 3.1 to 2.8. The Shurflo Aqua King II Supreme 5.0 leads on efficiency and flow. The Shurflo Aqua King II Premium 4.0 wins on value. The Shurflo Aqua King II Premium 4.0 costs $122.76 less ($236.33 vs $359.09).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
A marine-grade 4 GPM pump for boats and larger RVs with several fixtures. It costs more than pumps with similar flow and pressure.
Amazon $236.33Which should you buy?
- Choose the Shurflo Aqua King II Supreme 5.0 for efficiency (0.71 GPM per amp (7 A max) vs 0.40 GPM per amp (10 A max)) and flow (5 GPM rated open flow vs 4 GPM rated open flow).
- Choose the Shurflo Aqua King II Premium 4.0 for value ($59.08 per GPM ($236.33, 4 GPM) vs $71.82 per GPM ($359.09, 5 GPM)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 4 GPM and up RV water pump; a clear win is highlighted. How we rank explains each one.
| Factor weight | Shurflo Aqua King II Supreme 5.0 | Shurflo Aqua King II Premium 4.0 |
|---|---|---|
| Overall rating | 3.1/5 | 2.8/5 |
| Value 25% | 0 $71.82 per GPM ($359.09, 5 GPM) | 11 $59.08 per GPM ($236.33, 4 GPM) |
| Flow 20% | 75 5 GPM rated open flow | 50 4 GPM rated open flow |
| Pressure 15% | 71 55 psi shut-off | 71 55 psi shut-off |
| Efficiency 10% | 100 0.71 GPM per amp (7 A max) | 43 0.40 GPM per amp (10 A max) |
| Features 15% | 65 internal bypass, runs dry without damage, thermal protection, strainer included | 65 internal bypass, runs dry without damage, thermal protection, strainer included |
| Warranty 15% | 0 warranty not published, scored as none | 0 warranty not published, scored as none |
Specifications
| Shurflo Aqua King II Supreme 5.0 | Shurflo Aqua King II Premium 4.0 | |
|---|---|---|
| Performance | ||
| Rated open flow | 5 GPM | 4 GPM |
| Shut-off pressure | 55 psi | 55 psi |
| Max current draw | 7 A | 10 A |
| Price per GPM | $71.82 | $59.08 |
| Self-priming lift | 6 ft | 6 ft |
| Features | ||
| Control | Pressure switch | Pressure switch |
| Diaphragm chambers | 4 | 4 |
| Internal bypass | Yes | Yes |
| Runs dry | Yes | Yes |
| Thermal protection | Yes | Yes |
| Strainer included | Yes | Yes |
