Zoeller M63 Premium
#9 in Up to 1/3 HPFull review
For owners who want the longest lasting 1/3 HP class pump and are willing to pay for an all cast iron build and a 5 year warranty.
Amazon $311.25$311.25
The Zoeller M63 Premium is the better sump pump overall, rated 3.0 to 3.0. The Zoeller M63 Premium leads on warranty and build. The Liberty Pumps S37 wins on value. The Liberty Pumps S37 costs $146.25 less ($165 vs $311.25).
Liberty Pumps S37
#12 in Up to 1/3 HPFull review
For a newer house or a gritty pit where a low cost Liberty pump that resists debris jams is enough.
Amazon $165$165
Prices were last checked October 31, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Zoeller M63 Premium for warranty (5-year warranty vs 3-year warranty) and build (cast iron motor housing, switch fits a narrow pit vs switch fits a narrow pit).
- Choose the Liberty Pumps S37 for value ($78.57 per 1,000 GPH at 10 ft ($165, 2,100 GPH) vs $152.57 per 1,000 GPH at 10 ft ($311.25, 2,040 GPH)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every up to 1/3 HP sump pump; a clear win is highlighted. How we rank explains each one.
| Factor weight | Zoeller M63 Premium | Liberty Pumps S37 |
|---|---|---|
| Overall rating | 3.0/5 | 3.0/5 |
| Value 30% | 0 $152.57 per 1,000 GPH at 10 ft ($311.25, 2,040 GPH) | 43 $78.57 per 1,000 GPH at 10 ft ($165, 2,100 GPH) |
| Flow 30% | 36 2,040 GPH at 10 ft | 40 2,100 GPH at 10 ft |
| Build 20% | 67 cast iron motor housing, switch fits a narrow pit | 33 switch fits a narrow pit |
| Warranty 20% | 100 5-year warranty | 50 3-year warranty |
Specifications
| Zoeller M63 Premium | Liberty Pumps S37 | |
|---|---|---|
| Pumping | ||
| Motor | 0.3 HP | 1/3 HP |
| Type | Submersible | Submersible |
| Flow at 10 ft | 2,040 GPH | 2,100 GPH |
| Max lift | 19.2 ft | 25 ft |
| Discharge | 1.5 in | 1.5 in |
| Running current | 9.7 A | 6.5 A |
| Switch and build | ||
| Switch | Vertical float | Vertical float |
| Cast iron housing | Yes | - |
| Alarm or monitoring | No | No |
| Wi-Fi | No | No |
| Cord length | 9 ft | 10 ft |
| Weight | 23 lb | 14 lb |
| Warranty | 5 years | 3 years |