The Hawkesbury-Nepean has flooded repeatedly and severely in recent years, and vehicles caught in those events do not simply disappear. Some are written off and dismantled. Some are repaired and returned to the road. Some are sold privately by owners who describe them, accurately enough, as having been "in the water briefly."
On a petrol car that is a serious problem. On an electric or hybrid vehicle it is a different order of problem, and it deserves a page of its own rather than a line in a checklist.
What water actually does to a high-voltage pack
A traction battery is sealed, and a sealed pack that has been briefly splashed is usually fine. The concern is submersion — water sitting against seals, connectors and vents for hours, sometimes with silt in it.
Where water does get in, the consequences are not like a wet carpet:
- Corrosion of connectors, busbars and voltage-sense wiring, which can produce intermittent faults and inaccurate cell readings long after the vehicle looks and drives normally
- Cell-level damage and imbalance, which may take weeks or months to show
- A genuine fire risk, which is why emergency services and manufacturers treat submerged electric vehicles with caution and recommend quarantine and inspection rather than simply drying them out
Salt water is substantially worse than fresh, so a Hawkesbury river flood is not the worst case. It is still a case where "it started fine afterwards" proves very little.
Being straight about what our test does and does not cover
A battery diagnostic is not a flood-damage inspection, and we will not pretend otherwise.
What it does: read the battery management system's own State of Health and cell-level data, show whether cells have drifted apart, and surface stored and pending high-voltage fault codes — including ones that have not yet triggered a dashboard light. On a vehicle that has taken water, cell imbalance and pending codes are exactly the sort of early evidence worth having.
What it does not do: inspect seals, look inside the pack, assess corrosion, or tell you whether water ever entered. It cannot. If you suspect a vehicle has been submerged, you want a PPSR check and a thorough mechanical inspection as well as a battery read, and honestly, on a vehicle you suspect has been under water, the sensible answer is usually to buy a different vehicle.
What to check before you buy anything in a flood area
Run a PPSR check first. It costs a few dollars and shows whether the vehicle is recorded on the written-off vehicles register. A repairable write-off can be legally returned to the road in New South Wales, and it will still be a repairable write-off on the record. Do this before you inspect, not after.
Ask directly, and ask twice. "Has this vehicle ever been in flood water, at any depth?" Then ask where it was garaged during the flood events. Owners are usually straight about it when asked plainly.
Look for the physical signs a mechanical inspection will catch: silt in the spare wheel well, under carpets and in seat rails; water lines inside the tailgate or door cavities; corrosion on bolts and brackets that should be clean on a vehicle of that age; a musty smell that air freshener is working hard against.
Then have the battery read, for fault codes, cell voltage spread and temperature behaviour.
Where we come to
Windsor, South Windsor, Bligh Park, McGraths Hill, Pitt Town, Wilberforce, Freemans Reach, Glossodia, Mulgrave and Vineyard. Home addresses, seller addresses and dealerships.
Booking
Online booking is open for all Hawkesbury postcodes. $249, no travel surcharge. Phone 02 7252 1390 if you want to talk through a specific vehicle first.
Richmond · Battery test vs pre-purchase inspection · Western Sydney · Book a test — $249