Every well pump gets a score from 0 to 100% built from four 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 into jet pumps, 1/2 HP submersibles and submersibles of 3/4 HP and up, and value and flow have their own scale for each group.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per gallon a minute at the rating point | 30% |
| Flow | gallons a minute at the rating point | 25% |
| Housing | what the pump body is made of | 15% |
| Warranty | warranty length | 30% |
Where the numbers come from
Flow is read from the maker’s performance table or curve at one fixed rating point, so every pump in a group is compared at the same depth: 200 ft of total head for submersibles, and 20 ft to water at 40 psi for jet pumps. Housing, wiring and warranty come from the maker’s spec sheet, manual or product page. Prices are checked at Amazon, the maker’s own store and home improvement and pump retailers, and the lowest is used.
The factors
Value is the current price divided by the flow at the rating point, on a log scale, so going from $80 to $40 per gpm counts as much as going from $40 to $20. For jet pumps, $90 per gpm scores zero and $20 full marks; for submersibles, $120 and $30.
Flow is gallons a minute at the rating point. Jet pumps score zero at 4 gpm and full marks at 12; 1/2 HP submersibles, 3 and 12; submersibles of 3/4 HP and up, 6 and 20. A pump that can’t lift water to 200 ft at all scores zero.
Housing is what the pump body is made of. Stainless steel scores full marks, cast iron 80 and thermoplastic 30: a well pump runs for years in water that can be hard, sandy or acidic.
Warranty is the warranty length: 1 year scores zero and 5 years full marks.
What isn’t scored
Voltage, wiring, current draw, impeller material, discharge size and the deepest the pump can reach are listed but not scored. Stainless steel and 2-wire pumps have their own pages.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as 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.