Can My Pump Keep Up?

When groundwater or storm runoff surges, a sump pump has one job: keep the inflow below the outflow. Enter your pump specs and head height, then estimate or input inflow. You’ll get a clear “can it keep up?” verdict, duty cycle, and a backup battery runtime plan—no guesswork.

Can My Pump Keep Up?

Check if your sump pump’s capacity at your head height is greater than estimated inflow. Then size a backup battery and see how long it can run at your actual duty cycle.

GPM
Use the pump curve rating at your actual head height (see label/manual).
ft
Vertical lift + a bit for elbows/hose. This doesn’t change capacity entered above; it’s noted for your records.
GPM
If unknown, switch to “Estimate Inflow.”
% extra
Adds required headroom so the pump isn’t maxed out.
Peak short-burst intensity during storms (e.g., 1–3 in/hr).
sq ft
Footing drains + part of yard/roof that actually routes into the pit.
% of that area
How much of that area truly reaches the sump (50–80% typical).
GPM / 100 ft perimeter
Crude allowance for saturated soils. Set to 0 if unknown.
ft
Needed only if seepage above is nonzero.
Ah @ 12V (per battery)
Common deep-cycle: 80–120 Ah. Enter per battery capacity.
batteries
% (usable)
50% for flooded/AGM, 80–90% for lithium.
% (inverter/controller losses)
amps @ 120V AC
If unknown, many 1/3–1/2 HP pumps draw 4–7 A under load.
GPM
GPM
Enter your pump’s GPM at head (or backup pump’s rating).
Don’t have the pump curve?
A rough flow estimate from horsepower is: GPM ≈ (HP × 3960 × efficiency) / head(ft). With 45% efficiency: GPM ≈ HP × 1782 / head. Use cautiously—manufacturer curves are best.
Good practice
Keep 20–30% capacity headroom, add a second pump on a separate circuit, and install a high-water alarm. Test check valves and clear discharge lines.

This tool provides planning estimates; verify against your pump’s official curve and local conditions.