{ "slug": "well-pump-energy", "title": "Well Pump Energy Cost Calculator", "heading": "Well Pump Electricity Cost Calculator", "category": "financial", "url": "https://www.revenuelab.fyi/toolbox/well-pump-energy", "summary": "Annual cost to run your well pump based on usage and horsepower.", "description": "Estimates annual electricity cost for a residential well pump using motor horsepower, daily water usage, and pump flow rate to derive actual runtime, rather than assuming a flat number of hours. Well pumps are intermittent loads — they cycle on when the pressure tank drops below its cut-in setting and off at cut-out — so daily runtime depends on household water demand divided by the pump's flow rate (gallons per minute), not a fixed schedule. This also matters for the battery-backup and generator-sizing decisions, since well pumps are usually the highest-surge-load, most critical circuit to keep powered during an outage for households on a private well.", "formula": "Daily runtime (hrs) = daily gallons used ÷ (pump GPM × 60); kW draw = HP × 0.746 ÷ efficiency; annual cost = kW × daily hours × 365 × rate.", "dateModified": "2026-09-30", "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=well-pump-energy", "inputs": [ { "id": "pumpHp", "label": "Well pump size", "kind": "number", "hint": null, "default": 0.75, "unit": "HP", "min": 0.25, "max": 3 }, { "id": "pumpGpm", "label": "Pump flow rate", "kind": "number", "hint": null, "default": 10, "unit": "GPM", "min": 2, "max": 30 }, { "id": "dailyGallons", "label": "Household daily water use", "kind": "number", "hint": null, "default": 300, "unit": "gal", "min": 20, "max": null }, { "id": "efficiency", "label": "Motor efficiency", "kind": "number", "hint": null, "default": 65, "unit": "%", "min": 40, "max": 90 }, { "id": "elecRate", "label": "Electricity rate", "kind": "number", "hint": null, "default": 0.16, "unit": "$/kWh", "min": 0.02, "max": 0.6 } ], "outputs": [ { "id": "annualCost", "label": "Annual well pump electricity cost", "format": "currency", "hint": null, "primary": true }, { "id": "dailyHours", "label": "Estimated daily runtime", "format": "decimal", "hint": null, "primary": false }, { "id": "annualKwh", "label": "Annual energy use", "format": "number", "hint": null, "primary": false }, { "id": "surgeWatts", "label": "Estimated motor startup surge", "format": "number", "hint": null, "primary": false } ], "worked_example": { "inputs": [ "Well pump size: 0.75 HP", "Pump flow rate: 10 GPM", "Household daily water use: 300 gal", "Motor efficiency: 65 %", "Electricity rate: 0.16 $/kWh" ], "outputs": [ "Annual well pump electricity cost: $25", "Estimated daily runtime: 0.5", "Annual energy use: 157", "Estimated motor startup surge: 2,152" ] }, "how_to": { "title": "How to use this", "steps": [ "Enter well pump size (HP).", "Enter pump flow rate (GPM).", "Enter household daily water use (gal).", "Enter motor efficiency (%).", "Enter electricity rate ($/kWh).", "Read your annual well pump electricity cost on the right — it updates as you type.", "Hit Share to keep the scenario or send it to someone." ] }, "scenarios": [ { "name": "Conservative", "description": "Lower-end numbers — what if things land soft?", "values": { "pumpHp": 0.44999999999999996, "pumpGpm": 6, "dailyGallons": 180, "efficiency": 40, "elecRate": 0.096 } }, { "name": "Typical", "description": "Defaults — the most common real-world setup.", "values": { "pumpHp": 0.75, "pumpGpm": 10, "dailyGallons": 300, "efficiency": 65, "elecRate": 0.16 } }, { "name": "Ambitious", "description": "Higher-end numbers — what if things really pop?", "values": { "pumpHp": 1.2000000000000002, "pumpGpm": 16, "dailyGallons": 480, "efficiency": 90, "elecRate": 0.256 } } ], "limitations": [ "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.", "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.", "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant." ], "faq": [ { "q": "Why does a well pump matter so much for backup power?", "a": "No pump means no water at all — not just for drinking, but for flushing toilets and fighting fires if you're on well water. It's also one of the highest-surge loads in a house (2.5-3x running watts at startup), which is why it's the first thing to check against a generator's or battery's surge rating during outage planning." }, { "q": "How do I find my pump's GPM and HP?", "a": "Both are usually on the pump's nameplate, often stamped on the motor housing itself or in the well completion report from when the well was drilled. If you can't access it, a well contractor can measure flow rate directly, and typical residential submersible pumps run 0.5-1.5 HP with 8-15 GPM." }, { "q": "Why is well pump motor efficiency lower than other appliances?", "a": "Submersible well pump motors are optimized for reliability in a sealed, water-cooled environment rather than peak efficiency, and older pumps especially can run 50-65% wire-to-water efficiency. A newer, correctly-sized pump can improve this meaningfully and also reduce the well's short-cycling if the pressure tank is properly sized." }, { "q": "Does a bigger pressure tank reduce energy cost?", "a": "Indirectly — a larger pressure tank means longer run cycles and fewer starts per day, which reduces motor wear and the energy penalty of frequent startup surges, though it doesn't change total daily runtime much since that's driven by total water used, not cycle frequency." } ], "related": [ "https://www.revenuelab.fyi/toolbox/pool-pump-energy-cost", "https://www.revenuelab.fyi/toolbox/generator-sizing-fuel", "https://www.revenuelab.fyi/toolbox/battery-backup-runtime" ], "license": "CC-BY-4.0", "citation": "RevenueLab — Well Pump Energy Cost Calculator (https://www.revenuelab.fyi/toolbox/well-pump-energy)" }