Every pump gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Pumps are grouped by motor size, up to 1/2 HP and 3/4 HP and up.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per gallon a minute at 10 ft of head | 30% |
| Flow | flow at 10 ft of head | 20% |
| Lift | flow at 20 ft of head | 15% |
| Build | cast iron housing | 10% |
| Warranty | warranty length | 25% |
Where the numbers come from
Flow, head, solids size, housing and warranty come from the maker’s pump curve, spec sheet or product page. Flow at 10 and 20 ft is read from the maker’s flow table, or from the pump curve where no table is published. Prices are checked at Amazon, the maker’s own store and home improvement retailers, and the lowest is used.
The factors
Value is the current price divided by the flow at 10 ft of head, on a log scale, so halving the price per gpm always counts the same. $7 per gpm scores zero and $2 full marks.
Flow is the maker’s flow at 10 ft of total head, a typical basement lift. For pumps up to 1/2 HP 40 gpm scores zero and 120 gpm full marks; for 3/4 HP and up, 90 gpm scores zero and 170 gpm full marks.
Lift is the maker’s flow at 20 ft of total head, which shows how well the pump keeps up on a high or long run. A pump whose shutoff head is under 20 ft scores zero. For pumps up to 1/2 HP 0 gpm scores zero and 60 gpm full marks; for 3/4 HP and up, 30 gpm scores zero and 130 gpm full marks.
Build is full marks for a cast iron motor housing and volute, which shed heat and last longer, and zero for a plastic or composite housing.
Warranty is the maker’s warranty: 1 year scores zero and 5 years full marks.
What isn’t scored
Solids size (every ranked pump passes 2 in), shutoff head, the switch type, discharge size, current draw, cord length and weight are listed but not scored.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as the shortest warranty on the scale, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.