A livestock watering point is one of the highest-value solar applications on a farm, because the alternative is a diesel pump, a long pipeline or daily hauling. The design problem is simple but unforgiving: it must deliver water every day of the dry season with nobody watching.
Start from water demand, not from panels
| Animal | Daily water need |
|---|---|
| Cattle (beef) | 30-60 litres per head |
| Cattle (dairy) | 60-120 litres per head |
| Sheep / goats | 4-10 litres per head |
| Horses | 30-50 litres per head |
| Pigs | 10-20 litres per head |
Demand rises sharply with temperature and lactation, so size on the hottest month, not the annual average. Add 10-15 percent for spillage, cleaning and evaporation from the trough.
Total head
Total head is static lift plus drawdown plus delivery height plus friction. For a borehole serving a trough 300 m away, friction can easily exceed the static lift if the pipe is undersized — a 25 mm line carrying 3 m³/day over 300 m loses several metres of head.
Two practical rules: use at least 32 mm delivery pipe for runs over 100 m, and keep the number of elbows and fittings to a minimum.
Storage is the buffer
Because pumping happens only while the sun shines, the tank is what actually delivers water. Size it for one to two days of demand so that a cloudy day does not stop watering. Elevated tanks add pressure for gravity flow; ground tanks need a small pressure pump, which adds a load and a failure point.
Trough and float valve
- Use a float valve rated for the flow, and fit a strainer upstream
- A trough that empties and refills repeatedly keeps water cooler and cleaner than a large still tank
- Provide a shaded or partially buried trough in hot climates to limit evaporation and algae
- Add a low-level cut-out so the pump never runs dry if the float sticks
Cold climates
Where temperatures drop below freezing, the constraint changes entirely: exposed pipes and troughs ice up, and a pump pushing into a frozen line will deadhead and fail. Options include a frost-free trough with a buried supply line below the frost depth, drain-back plumbing that empties on shutdown, or a small tank inside a sheltered structure.
Security and livestock damage
Panels and controllers on open range attract damage — from livestock rubbing, from thieves, and from wildlife chewing cable. Practical measures: mount the array on a fenced frame or above animal reach, run cable in steel conduit, and use tamper-resistant fixings on the controller enclosure.
FAQ
How many cattle can a small solar pump water?
A 1 kWp array driving a submersible at moderate head typically delivers several cubic metres a day — enough for 50-100 head, depending on head and sun hours. Always calculate from demand and head rather than from a rule of thumb.
Do I need a battery for a livestock watering system?
Usually not. Pumping into a tank during daylight, with the tank sized for a day or two of demand, removes the battery entirely and is far cheaper per litre.
What happens in the dry season when the borehole yield drops?
The pump must be matched to the sustainable yield, not the test-pumping peak. Pumping a borehole harder than it recovers damages the source and the pump.
Tell us your head, daily water need and location and we will size the pump and array. Request a sizing proposal or see sizing solar water pumping.