Pump Cavitation: Stop It Before It Breaks Your Off-Grid System

By Sarah Chen · environmental engineer · water, waste and everything that flows downhill

“My pump died at 3am after 45,000 cavitation bubbles chewed through the impeller, leaving me without water in the drought.”

Cavitation isn't some fancy engineering term. It's when your pump starts sucking air instead of water. And it'll destroy your system faster than a dingo on a chicken coop. Let's cut the crap and fix it.

What Causes Cavitation (No Bullshit)

• Pump too high above water source (bore, tank, dam)
• Air leaks in suction pipe (cracked joints, loose fittings)
• Running pump dry (tank empty, bore low)
• Wrong pipe size (too small = too much friction)
• Water too hot (rare in Australia, but happens in summer)

Why It Matters (You'll Regret Ignoring This)

It doesn't just make noise. It:

• Makes that awful "gravel in the pump" sound (you'll hear it from the shed)
• Wears out impellers in weeks (not years)
• Reduces water pressure to zero
• Costs you $500+ for a new pump (and a day's work)

How to Stop It (Practical Fixes)

Rule #1: Get the pump below the water level. Always. If your bore's at 10m depth, the pump must be at 11m or lower. No exceptions.

Rule #2: Fix air leaks immediately. Run soapy water over every joint. Bubbles = leak. Replace the faulty part. Don't wait.

Rule #3: Use the right pipe size. 25mm pipe? Use 32mm. Seriously. 25mm is a death wish for anything over 5m suction. Bunnings sells 32mm PVC for $18/m. Get it.

Rule #4: Install a foot valve. Non-negotiable. Stops water draining back into the bore when the pump shuts off. $35 at Pump Warehouse. Do it.

Australian Suppliers & Pricing (No Markups)

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.