Short answerThe simplest reliable design is a solar well pump that fills a cistern or raised tank by day, with gravity or a small battery-powered booster pump giving pressure at the taps. Pumping straight into a pressure tank works but adds 92 to 139 ft of head at 40 to 60 psi.
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Key takeaways
- Adding house pressure to a well pump's head can double its energy use.
- A gravity tank or a cistern with a small booster is usually the simplest design.
- Test a private well for bacteria and nitrate at least once a year.
Safety. Panels and batteries can deliver dangerous current. Follow NEC Article 690 and local code, and use a licensed electrician or well contractor where your state requires one.
How much a house uses
The EPA puts average US home use at about 82 gallons per person per day, indoor and outdoor. Off-grid households with low-flow fixtures and no lawn commonly use far less. The calculator defaults to 50 gallons a person; change it to match your fixtures and habits.
Three working designs
- Gravity tank. The solar pump fills a tank on a hill or tower; the house draws by gravity. No battery, no pressure switch. Each 2.31 ft of height is 1 psi, so 30 to 40 psi needs a tank 70 to 90 ft above the taps.
- Cistern plus booster. The solar pump fills a cistern near the house; a small 12V or 24V pressure pump with its own pressure switch draws from it, running off the house battery. The well pump never needs a battery.
- Battery-powered well pump into a pressure tank. The most like a grid house, and the most energy-hungry: the well pump has to lift the water and supply the full house pressure, often 40 to 60 psi, which adds 92 to 139 ft of head.
Why designs 1 and 2 are popular
Adding 40 psi to a well pump's head can double its energy use. Pumping slowly to a cistern at low head and boosting only what the house draws is usually cheaper in panels and gentler on the well. It also keeps a reserve of water on hand when the sun has been gone for a week.
Eco-Worthy 100W 18V monocrystalline panel
The building block for a 12V or 24V pump array, or a battery-charging array.
- Power
- 100 W
- Nominal
- 12V class (18V)
- Packs offered
- 1, 2 or 4
on eco-worthy.com, 18 October 2026
Eco-Worthy 400W 12V off-grid kit
A battery-buffered 12V pumping system: panels, MPPT controller, brackets and cables in one box.
- Panels
- 4 x 100 W (Vmp 20.2V, Voc 24.5V)
- Controller
- 40A MPPT, 12V/24V, under 100V PV input
- Mounting
- Z brackets
- Battery
- Not in the base kit (optional bundles add one)
on eco-worthy.com, 18 October 2026
Eco-Worthy 12V 100Ah LiFePO4 battery
1.28 kWh of storage for night or cloudy-day pumping. Low-temperature charge protection.
- Chemistry
- LiFePO4
- Capacity
- 12.8V 100Ah (about 1.28 kWh)
- Extras
- Bluetooth, low-temperature protection
on eco-worthy.com, 18 October 2026
We have not tested these products; specifications are the merchant's own. Affiliate disclosure.
Water quality
A private well is the owner's responsibility to test. Test for bacteria and nitrate at least yearly and after any work on the well, and for the contaminants common in your area. Your state or county health department lists certified labs.
Two people on a well with a 24V battery system, as a starting point.