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About this tool
Find how long a pump takes to fill your water tank, plus the units and rupees each fill costs at your head and efficiency.
A water tank refill time calculator divides the litres still missing from the tank by the net rate water enters it — the pump's discharge minus anything drawn off taps at the same time — to give the minutes the pump must run. It then prices the fill using the hydraulic power equation P = ρgQH with ρ = 998 kg/m³ and g = 9.80665 m/s², divided by the pump's wire-to-water efficiency, so you see both the running time and the units of electricity each fill consumes.
Open Water Tank Refill Time Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Subtracts taps running during the fill instead of assuming a closed system.
Uses the ρgQH hydraulic power equation and your own efficiency figure.
Turns running minutes into kilowatt-hours and rupees at your tariff.
A typical 1 HP domestic monoblock delivering about 60 litres a minute fills an empty 1,000 litre tank in roughly 17 minutes. The real figure depends on the lift: discharge falls along the pump curve as head rises, so the same pump lifting 30 m may deliver only half its rated flow.
Filling 1,000 litres to a 12 m head takes about 0.033 kWh of hydraulic energy, which becomes roughly 0.055 kWh at the meter for a pump running at 60% wire-to-water efficiency — under one rupee at a ₹8 per unit tariff. Cost scales directly with both the litres and the height they are lifted.
Total head is the vertical distance from the water level in the sump to the tank inlet, plus friction losses in the pipe and fittings. For a short, correctly sized domestic line, adding about 10% to the static lift is the usual allowance; long runs, narrow pipe or many bends need considerably more.
The three usual causes are a pump discharging below its rated flow because of the head, taps or a flush drawing water during the fill, and a partly clogged foot valve or strainer. Enter your measured flow — time how long the pump takes to fill a known bucket — rather than the rating on the nameplate.
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