Wassermann 3WDP4 4.0 GPM 45 psi
#7 in 4 GPM and upFull review
A low-cost 4 GPM pump for a trailer owner who wants more flow than the stock pump. Its sibling 5 GPM model costs only a few dollars more.
Amazon $59.99$59.99
The Wassermann 3WDP4 4.0 GPM 45 psi is the better RV water pump overall, rated 3.3 to 2.8. The Wassermann 3WDP4 4.0 GPM 45 psi leads on value, features and pressure. The Wassermann 3WDP4 4.0 GPM 45 psi costs $125.10 less ($59.99 vs $185.09).
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.
Johnson Pump Aqua Jet WPS 4.0
#12 in 4 GPM and upFull 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 $185.09$185.09
Which should you buy?
- Choose the Wassermann 3WDP4 4.0 GPM 45 psi for value ($15 per GPM ($59.99, 4 GPM) vs $46.27 per GPM ($185.09, 4 GPM)), features (runs dry without damage, strainer included vs none of the listed features) and pressure (45 psi shut-off vs 41 psi shut-off).
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 | Wassermann 3WDP4 4.0 GPM 45 psi | Johnson Pump Aqua Jet WPS 4.0 |
|---|---|---|
| Overall rating | 3.3/5 | 2.8/5 |
| Value 25% | 100 $15 per GPM ($59.99, 4 GPM) | 27 $46.27 per GPM ($185.09, 4 GPM) |
| Flow 20% | 50 4 GPM rated open flow | 50 4 GPM rated open flow |
| Pressure 15% | 43 45 psi shut-off | 31 41 psi shut-off |
| Efficiency 10% | 50 maximum current draw not published (neutral score used) | 50 maximum current draw not published (neutral score used) |
| Features 15% | 30 runs dry without damage, strainer included | 0 none of the listed features |
| Warranty 15% | 0 warranty not published, scored as none | 67 3-year warranty |
Specifications
| Wassermann 3WDP4 4.0 GPM 45 psi | Johnson Pump Aqua Jet WPS 4.0 | |
|---|---|---|
| Performance | ||
| Rated open flow | 4 GPM | 4 GPM |
| Shut-off pressure | 45 psi | 41 psi |
| Price per GPM | $15 | $46.27 |
| Features | ||
| Control | Pressure switch | Pressure switch |
| Runs dry | Yes | - |
| Strainer included | Yes | - |
| Build | ||
| Weight | - | 4.5 lb |
| Warranty | - | 3 years |