Solar Well Pumps: Submersible vs Surface for Aussie Off-Grid
Stop wasting money on the wrong pump. You need to know this before you buy.
Stop wasting money on the wrong pump. You need to know this before you buy.
Comparison of submersible and surface solar well pumps with shared panel-driven setup and tank storage.
Submersible vs Surface: The Real Deal
Submersible (pump in the well):
Best for wells deeper than 10m. If your water's below 10m, you're screwed with surface.
No priming needed. Just drop it in and go.
Quieter. You won't hear it whining at 3am.
Price: $1,200–$3,500 (Aussie brands). Don't buy cheap Chinese ones – they die in 6 months.
Downside: If it fails, you're pulling the whole pump out of the well. Costly.
Surface (pump above ground):
Only for shallow wells (max 7–8m depth). If your well's deeper, forget it.
Cheaper upfront ($500–$1,500) and easy to fix.
Needs priming. If the well runs dry, you burn the pump. Happens every summer.
Only use if you have a reliable water table. Not for dry areas.
Biggest Aussie mistake: Buying a surface pump for a 12m well. It'll sit there doing nothing. You'll waste $1,000 and 3 months of frustration.
Head Calculation: Don't Guess, Calculate
Head = Vertical lift (m) + Friction loss (m). You need this number to pick the right pump.
Example: Your well is 8m deep. You need to lift water 2m to the tank. Total vertical lift = 10m.
Friction loss: For 20mm pipe, every 10m adds ~1.5m head. If you have 15m of pipe, that's +2.25m.
Total head = 10m + 2.25m = 12.25m
Buy a pump rated for AT LEAST 13m head. If it's rated 12m, you'll get 30% less flow.
Use the Solar Water Pumps head calculator (free, Aussie-made). Don't eyeball it.
Practical Tips: What They Won't Tell You
Don't run the pump dry. Install a low-water cut-off. $50. Worth it.
Size your solar array right. A 100W panel runs a tiny pump. For a 10m head, you need 200–300W. Get a solar controller (like the Renogy 12V) to prevent battery drain.
Test the pump before you bury it. Run it for 24 hours on a test rig. If it fails, you're not stuck in a hole.
Check your water table. If it drops below 10m in summer (like in NSW or QLD), get a submersible. Surface pumps will die.
Always get a spare pump. They break. It's not a matter of if, but when.
Australian Suppliers & Pricing (indicative prices)
Submersible: $2,000–$4,000 (for 20m+ head). Includes installation quote.
Get a quote. Don't buy off the shelf for deep wells.
Price reality: $500 surface pump = $1,000 headache later. $1,500 submersible = 5 years of water. Do the math.
The Bottom Line
Submersible for wells deeper than 10m. Surface only if your well is shallow AND you have a reliable water table. Calculate head. Buy for the worst-case scenario (summer drought). Get a spare pump. Use Aussie suppliers – no Chinese junk. If you skip this, you'll be buying another pump in 6 months. Simple.
⚠️ SAFETY WARNING: Working with electrical systems, structural modifications, or gas installations carries inherent risks. If you are not confident in your abilities, always engage a licensed professional.
It cuts through the sales fluff and spells out the head, flow and voltage specs you need to match your bore, so you can pick the right pump without guessing.— Dave Miller
When to Call a Professional
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Electrical work beyond basic 12V DC additions — requires a licensed electrician
Structural modifications to buildings or load-bearing elements
Gas line installation or modification
Solar array installations above safe voltage thresholds
Any work that affects the structural integrity of your property
Always check local regulations and obtain necessary permits before commencing work.
