Home › Compare
Compare
Quick answer: To compare sump pumps fairly, line them up by gallons per hour at your own total dynamic head, not the zero-foot headline. Then check shut-off head, running amps, switch type for your pit, housing material, duty rating and warranty. A pump that clears your target flow with margin at your head, and fits your pit, is the right shortlist.
Why most comparisons go wrong
Store shelves and product listings tend to compare sump pumps by horsepower and maximum GPH. Both numbers are real but rarely useful on their own. Maximum GPH is usually measured at zero feet of lift, which no basement has. Horsepower describes the motor, not the water delivered. Two pumps can be equal on both headlines and still differ by a third in the flow they actually deliver at ten or fifteen feet. This hub gives you a comparison method that works with any brand's published data.
Step 1: know your duty point
Before comparing anything, find two numbers. Your target flow comes from the size calculator: measured inflow plus a margin. Your head comes from the TDH calculator: vertical lift plus friction. Together they form a duty point such as "900 GPH at 12 feet". Write it down; every comparison below refers to it.
Step 2: build a comparison table
For each candidate, copy figures from the manufacturer's spec sheet or performance chart, not from third-party summaries. Use a table like this:
| Field | Pump A | Pump B | Pump C |
|---|---|---|---|
| GPH at 10 ft | |||
| GPH at 15 ft | |||
| Interpolated GPH at your head | |||
| Shut-off head | |||
| Running amps | |||
| Discharge size | |||
| Switch type and minimum pit diameter | |||
| Housing material | |||
| Duty rating | |||
| Warranty |
Fill in what you can; missing data is itself a signal. A product with no published performance at head is hard to size responsibly.
Step 3: apply the filters
- Flow at head. Drop any pump that does not exceed your target at your head with sensible margin.
- Shut-off head. Prefer pumps whose shut-off head is comfortably above your TDH; performance falls steeply near shut-off.
- Pit fit. Drop pumps whose switch needs a wider pit than you have — see basins.
- Electrical. Note running amps for your circuit and for any battery backup or generator.
- Cycle length. Check that a high-flow pump will not empty your pit in a few seconds; use the pit calculator.
Worked example: three hypothetical pumps
Duty point: 1,000 GPH at 12 feet in a 20-inch pit (about 1.36 gallons per inch, 7-inch drawdown, about 9.5 gallons per cycle).
| Pump A (1/3 HP) | Pump B (1/2 HP) | Pump C (1/2 HP) | |
|---|---|---|---|
| GPH at 10 ft | 1,800 | 2,700 | 2,100 |
| GPH at 15 ft | 1,100 | 2,000 | 1,300 |
| Est. GPH at 12 ft | 1,520 | 2,420 | 1,780 |
| Shut-off head | 19 ft | 26 ft | 21 ft |
| Running amps | 5.5 | 9.0 | 8.2 |
| Seconds to empty 9.5 gal | 22 | 14 | 19 |
All three clear 1,000 GPH. Pump A has about 50% margin and the lowest draw, which helps a battery backup last longer. Pump B has large margin but very short cycles in this pit. Pump C costs nearly as much power as B with far less flow. For this home, Pump A or B could be right depending on how wet the lot is; Pump C is the weakest value despite sharing B's horsepower label.
Illustrative note (2026-10-29): Pumps A, B and C are fictional, with figures invented on 2026-10-29 to demonstrate the method. They do not represent real products, and estimated flows use straight-line interpolation.
Step 4: weigh the soft factors
After the numbers, consider build quality, noise, ease of removing the pump (a union above the check valve helps), service availability and warranty terms. Read the manufacturer's installation manual before buying; it often reveals pit size requirements, weep hole guidance and approved switch types. Also consider the submersible vs pedestal choice if your pit is unusual.
Comparing backup pumps
Use the same method for battery backup pumps, but expect lower figures. Note the DC running amps and check how long a given battery will power the pump with the runtime calculator. For water-powered backups, compare removal rate at your water pressure and head, and the water consumed per gallon removed — see water-powered backup.
What we do not do on this page
We do not rank brands or publish "best pump" lists, and we do not take payment for placement. Specifications change, and model numbers are reused across revisions. Always check the current spec sheet for the exact model you are buying and have a licensed plumber confirm the fit.
Reading a performance curve correctly
Some manufacturers publish a graph instead of a table. Flow runs along one axis and head along the other, and the curve slopes down from maximum flow at zero head to zero flow at shut-off. Find your head on the vertical axis, move across to the curve, then drop down to read flow. If the manufacturer gives curves for several models on one chart, make sure you are tracing the right line. Units also catch people out: some charts show gallons per minute rather than per hour, and a few show metres and litres. Multiply GPM by 60 for GPH, and remember that one metre is about 3.28 feet. When a curve and a table disagree, ask the manufacturer which is current.
Comparing replacement against your old pump
If your existing pump coped with past storms, add it to the table as a baseline. A replacement that beats it at your head, draws similar current and fits the same pit is a low-risk swap.
Frequently asked questions
Is the pump with the highest GPH at head always best?
Not if it short-cycles in your pit or draws more current than your backup can support.
Where do I find performance at head?
In the manufacturer's spec sheet, manual or product page, often as a table at 5-foot steps.
Should I compare by price per GPH?
It can help once all candidates meet your duty point and fit your pit.