Rainwater Tank Not Switching to Mains? Why It Keeps Happening in Aura

I'm Damian, a licensed plumber and gas fitter who lives in Nirimba. This is one of the most common jobs I get across the Aura estate, and after seeing it on house after house, I've tracked down why it happens and how to fix it so it stays fixed.

Signs your tank isn't switching to mains

• Water pressure drops away or stops completely when the tank is low or empty
• Toilets, the washing machine or the garden tap won't fill or run
• The tank pump runs, but little or no water comes through
• Water comes back after rain refills the tank, then stops again in dry spells
• It was fixed before, and the same problem came back months later

Why it's so common in Aura and Caloundra South

Aura homes were built with rainwater tanks plumbed to supply the toilets, laundry and outside taps, with a rain to mains changeover valve that's meant to switch to town water automatically when the tank runs low. Because so many homes went in with the same setup, the same fault shows up again and again around Nirimba, Baringa, Bells Creek, Palmview and Caloundra West.

The valve itself usually looks perfect when you take it apart: no debris, no worn parts, nothing obviously wrong. That's why this fault fools a lot of people.

Why the usual fixes don't last

I went through the same process many plumbers do. Bleeding air from the mains side would get water flowing again for a while. Stripping and refitting the changeover valve would get it working again too. But on job after job, the call came back weeks or months later with the same problem.

That pattern was the clue. If the valve was faulty, a clean and refit wouldn't keep bringing it back. The real cause was in how the system was set up, not in the valve itself.

How I fix it properly

Once I'd seen it on enough Aura homes, I wrote up a detailed report and sent it to the valve manufacturer, then talked the fix through with them directly. The result is a proven fix that deals with the cause, not just the symptom, so your tank changes over to mains reliably every time it runs dry.

On most homes it's a straightforward job, done in a single visit. You get a fixed price before I start, and I test the changeover before I leave so you know it's working.

Please don't try this yourself

The parts involved are part of your home's backflow protection, which stops tank water getting back into the town water supply. It's regulated work that has to be done by a licensed plumber, and getting it wrong can put the mains supply at risk. Pumps also carry mains electricity. If your water has stopped, it's worth a call rather than a DIY attempt.

Frequently asked questions

Do I need a new valve or a new pump?

Usually not. In most of the Aura homes I've seen, the valve and pump are both fine. Replacing them often doesn't solve it, because the cause is how the system works together, not a failed part.

Why does it work again after it rains?

When the tank has water, the pump supplies the house and the changeover isn't needed. The fault only shows up when the tank runs low and the valve needs to switch to mains, so it often appears in dry spells.

Can I just bypass the tank?

A temporary bypass can get water back on in an emergency, but it shouldn't be left that way, and it needs to be done correctly to protect the mains supply. A proper fix means your tank keeps saving you water and the mains backup works when it's needed.

Which areas do you cover for this?

I live in Aura and regularly fix this across Nirimba, Baringa, Bells Creek, Palmview, Caloundra West, Little Mountain and the wider Caloundra area.

PAGE Tradie Plumbing & Gas, owner-operated and based in Nirimba. QBCC Licence 15559043. Fully insured. 170+ five-star Google reviews. See also: Plumber in Nirimba and Plumber in Caloundra West.