Seaflo 42 Series 3.0 GPM 55 psi
#1 in Under 4 GPMFull review
A strong-value 3 GPM replacement: 55 psi, a bypass and a 4-year warranty for about half the price of the name-brand equivalent.
Amazon $59.32$59.32
The Seaflo 42 Series 3.0 GPM 55 psi is the better RV water pump overall, rated 3.7 to 2.8. The Seaflo 42 Series 3.0 GPM 55 psi leads on value, pressure and features. The Johnson Pump Aqua Jet WPS 3.5 wins on flow. The Seaflo 42 Series 3.0 GPM 55 psi costs $78.17 less ($59.32 vs $137.49).
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.
Johnson Pump Aqua Jet WPS 3.5
#5 in Under 4 GPMFull review
A marine pressure pump with a 3-year warranty, for boats where 41 psi is plenty. RV owners after a firmer shower should look at 55 psi pumps.
Amazon $137.49$137.49
Which should you buy?
- Choose the Seaflo 42 Series 3.0 GPM 55 psi for value ($19.77 per GPM ($59.32, 3 GPM) vs $39.28 per GPM ($137.49, 3.5 GPM)), pressure (55 psi shut-off vs 41 psi shut-off) and features (internal bypass, runs dry without damage vs none of the listed features).
- Choose the Johnson Pump Aqua Jet WPS 3.5 for flow (3.5 GPM rated open flow vs 3 GPM rated open flow).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every under 4 GPM RV water pump; a clear win is highlighted. How we rank explains each one.
| Factor weight | Seaflo 42 Series 3.0 GPM 55 psi | Johnson Pump Aqua Jet WPS 3.5 |
|---|---|---|
| Overall rating | 3.7/5 | 2.8/5 |
| Value 25% | 82 $19.77 per GPM ($59.32, 3 GPM) | 38 $39.28 per GPM ($137.49, 3.5 GPM) |
| Flow 20% | 25 3 GPM rated open flow | 38 3.5 GPM rated open flow |
| Pressure 15% | 71 55 psi shut-off | 31 41 psi shut-off |
| Efficiency 10% | 51 0.43 GPM per amp (7 A max) | 50 maximum current draw not published (neutral score used) |
| Features 15% | 40 internal bypass, runs dry without damage | 0 none of the listed features |
| Warranty 15% | 100 4-year warranty | 67 3-year warranty |
Specifications
| Seaflo 42 Series 3.0 GPM 55 psi | Johnson Pump Aqua Jet WPS 3.5 | |
|---|---|---|
| Performance | ||
| Rated open flow | 3 GPM | 3.5 GPM |
| Shut-off pressure | 55 psi | 41 psi |
| Max current draw | 7 A | - |
| Price per GPM | $19.77 | $39.28 |
| Self-priming lift | 6 ft | - |
| Features | ||
| Control | Pressure switch | Pressure switch |
| Internal bypass | Yes | - |
| Runs dry | Yes | - |
| Build | ||
| Weight | - | 4.5 lb |
| Warranty | 4 years | 3 years |