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 and the Jabsco Par-Max HD4 are evenly matched, rated 3.3 and 3.2. The Wassermann 3WDP4 4.0 GPM 45 psi leads on value. The Jabsco Par-Max HD4 wins on pressure. The Wassermann 3WDP4 4.0 GPM 45 psi costs $105.61 less ($59.99 vs $165.60).
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.
Jabsco Par-Max HD4
#8 in 4 GPM and upFull review
A heavy-duty 4 GPM, 60 psi pump with a 3-year warranty at a fair price, for boats and RVs with two fixtures.
Amazon $165.60$165.60
Which should you buy?
- Choose the Wassermann 3WDP4 4.0 GPM 45 psi for value ($15 per GPM ($59.99, 4 GPM) vs $41.40 per GPM ($165.60, 4 GPM)).
- Choose the Jabsco Par-Max HD4 for pressure (60 psi shut-off vs 45 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 | Jabsco Par-Max HD4 |
|---|---|---|
| Overall rating | 3.3/5 | 3.2/5 |
| Value 25% | 100 $15 per GPM ($59.99, 4 GPM) | 34 $41.40 per GPM ($165.60, 4 GPM) |
| Flow 20% | 50 4 GPM rated open flow | 50 4 GPM rated open flow |
| Pressure 15% | 43 45 psi shut-off | 86 60 psi shut-off |
| Efficiency 10% | 50 maximum current draw not published (neutral score used) | 28 0.35 GPM per amp (11.5 A max) |
| Features 15% | 30 runs dry without damage, strainer included | 35 runs dry without damage, thermal protection |
| Warranty 15% | 0 warranty not published, scored as none | 67 3-year warranty |
Specifications
| Wassermann 3WDP4 4.0 GPM 45 psi | Jabsco Par-Max HD4 | |
|---|---|---|
| Performance | ||
| Rated open flow | 4 GPM | 4 GPM |
| Shut-off pressure | 45 psi | 60 psi |
| Max current draw | - | 11.5 A |
| Price per GPM | $15 | $41.40 |
| Self-priming lift | - | 8 ft |
| Features | ||
| Control | Pressure switch | Pressure switch |
| Diaphragm chambers | - | 4 |
| Runs dry | Yes | Yes |
| Thermal protection | - | Yes |
| Strainer included | Yes | - |
| Build | ||
| Weight | - | 5.6 lb |
| Warranty | - | 3 years |