Water pump (motor): units per month in Pakistan
Short answer. A 1 HP domestic water pump draws roughly 900 watts of input power. Running an hour a day is about 0.9 units daily and 27 units a month; on a poor supply where the pump runs two and a half hours it becomes nearer 68 units — and it runs every month of the year, not just in summer.
Power draw
- Low: 370 W
- Typical: 750 W — the figure used in every calculation below
- High: 1500 W
0.5 HP is about 370 W of shaft output but nearer 500 W of input; 1 HP is roughly 750 W output and around 900–1,000 W input after motor losses.
Units and cost by usage pattern
Each row is 750 W × the hours shown ÷ 1,000, over 30 days. The three cost columns exist because the rupee cost of a unit depends entirely on which slab your month lands in — the same consumption costs a light user and a heavy summer household very different amounts. Rates are illustrative and not a substitute for the tariff table printed on your own bill.
| Usage pattern | Units / day | Units / month | At Rs 12.5/unit | At Rs 27.5/unit | At Rs 36/unit |
|---|---|---|---|---|---|
| Overhead tank filling twice a day (1 hour total) | 0.75 | 22.5 | Rs 281 | Rs 619 | Rs 810 |
| Low pressure supply, pump runs longer (2.5 hours) | 1.88 | 56.3 | Rs 704 | Rs 1,548 | Rs 2,027 |
| Bore pump on a deep water table (4 hours) | 3 | 90 | Rs 1,125 | Rs 2,475 | Rs 3,240 |
Rate bands: Rs 12.5 — light user, protected (≈150 units/month); Rs 27.5 — average household (≈250 units/month); Rs 36 — heavy summer month (700+ units). This appliance runs all year, so the monthly figure applies in every cycle.
Horsepower is output, not input
Pumps are sold by horsepower, which describes shaft output. The electrical input is higher because the motor is not perfectly efficient — typically 20 to 30 per cent higher on small domestic motors.
So a 1 HP pump is a 900 to 1,000 watt load, not a 750 watt one. Using the nameplate horsepower directly understates the bill.
The float switch case
A pump filling an overhead tank without a float switch runs until somebody notices, which regularly means it runs long after the tank overflowed. That is pure waste of both water and electricity, month after month.
A float switch or an automatic level controller is inexpensive and pays for itself quickly in any household where the pump is manually started.
When a pump suddenly costs more
If run time creeps up without any change in water use, something has changed hydraulically: a falling water table, a partially blocked foot valve, a worn impeller, or a leak in the rising main.
A pump that used to fill the tank in twenty minutes and now takes forty is consuming twice the electricity for the same water. It is a common and invisible contributor to a rising bill.
How to use less
- Fit an automatic level controller so the pump stops when the tank is full.
- Track how long it takes to fill the tank; a rising figure is a fault indicator, not a fact of life.
- Fix leaks in the rising main and in taps — every leaked litre was pumped and paid for.
- Shift tank filling out of peak hours if you are on a time-of-use tariff.
- Size the pump to the head you actually have; an oversized pump throttled by a valve wastes energy continuously.
Frequently asked questions
How many units does a 1 HP water pump use in an hour?
Roughly 0.9 to 1 unit per hour of running, accounting for motor losses. A 0.5 HP pump uses about half that.
Does starting the pump frequently use more electricity than leaving it running?
Starting current is high but very brief, so on any realistic cycle the run time dominates. Do not leave a pump running to avoid restarts.
Compare with
- Electric geyser (storage water heater) — 2000 W typical
- Water dispenser — 550 W typical
- UPS / home inverter — 180 W typical
Go further
Filed under water heating and pumping in the full appliance index. Add your own hours in the consumption calculator, or open your actual bill with the reference number lookup.