Hawkesbury-Nepean floods and flood-affected Sydney homes
Infrastructure NSW’s review of the March and July 2022 Hawkesbury-Nepean floods records how hard the river system was hit. In March 2021 the Hawkesbury-Nepean was severely affected by flooding. Major flooding followed in March 2022 and July 2022, with further moderate flooding at Windsor in April and October 2022.
The March 2022 flood peaked 0.9 m higher than March 2021 at Windsor, the highest there since 1978. The July 2022 flood was 1.0 m higher than March 2021 at Windsor. Repeated events like these leave owners asking whether surfaces, cavities and contents that took in water have been dealt with, which is the question swab results can help answer.
NSW Health advice on floodwater and sewage
NSW Health’s factsheet on staying healthy during and after floods warns that floodwater and leftover debris may be contaminated with sewage, and that contact with floodwater should be kept to a minimum. It also says mould or mildew may develop if items are not completely dried, and that walls and floor cavities should be checked for trapped water or mud.
That is why bacteria and mould are often assessed together after water damage in Sydney. Where damp persists, mould inspection in Sydney covers the moisture side. The guide to bacteria after sewage and flood events explains what surface testing can show.
Flood history as a material fact for NSW rentals
A NSW landlord or agent must not knowingly hide from a prospective tenant that the property has been affected by flooding from a natural weather event or bushfire in the last five years. It is one of the material facts on the NSW Government page about what tenants need to be told about a rental property.
The wording refers to flooding from a natural weather event. It does not mention burst pipes or sewer overflows, and it sets no bacteria level. A report that records where contamination was found, and where it was not, gives landlords and tenants a shared starting point. This is general information, not legal advice.
Sydney jobs where bacteria swabs are requested
Common requests include:
- sewage coming up through a floor waste or shower drain in a ground-floor unit
- water from a burst pipe in the apartment above, running through ceilings and walls
- floodwater through the lower level of a house in the Hawkesbury or outer west
- a hoarded house, or a death not found for some days, before the family or owner decides on re-occupation
Sampling tells you most at two points. A round before cleaning documents the problem. A round afterwards shows what remains. Test Australia does not clean and takes no referral income, so both rounds come from a party with no stake in the work. See why independent testing matters and the types of assessment work we take on.
How swabs from a Sydney site are analysed
Suitably qualified occupational hygienists collect surface swabs from the areas in scope, record conditions on the day and log each swab under chain of custody. The scope fixes the organisms or indicator groups to be tested, so the numbers mean something for your question. The report names the laboratory and states any accreditation that applies. Test Australia itself is not NATA-accredited. Each result is set against a criterion the report names and explains.
Reports are available within 5 business days of the laboratory results being received. The national bacteria testing page covers organisms and methods in more detail, and the storm and flood season guide covers testing after severe weather. Our general approach is described on the methodology page.
Fees for bacteria testing across Greater Sydney
No two water events spread the same way, so there is no set price. The fee depends on the number of rooms or lots affected, whether testing happens before and after cleaning, the organisms in scope and travel beyond Greater Sydney. A written fee proposal sets this out for your Sydney property before any visit is booked. If the property also has fire damage or drug residue questions, see fire damage testing in Sydney or meth testing in Sydney. Start an enquiry through contact.
Steps for a Sydney bacteria assessment
- Describe the water event. Tell us what happened, when, which rooms or lots took water and whether any cleaning has started at the Sydney property.
- Fix the organisms and areas. The fee proposal names the organisms or indicator groups, the areas to swab and whether one or two rounds are planned.
- Swabbing on site. Suitably qualified occupational hygienists swab the agreed surfaces and record moisture and site conditions.
- Report against named criteria. The laboratory results are set against the criteria the report names. Reports are available within 5 business days of the laboratory results being received.
Sydney bacteria and flood questions
Does a NSW landlord have to disclose past flooding of a Sydney rental?
Yes, where it applies. NSW material facts include whether the property has been affected by flooding from a natural weather event or by bushfire in the last five years. A landlord or agent must not knowingly hide this from a prospective tenant to get them to sign. This is general information, not legal advice.
Does the NSW flood disclosure rule cover a burst pipe or sewer overflow?
The material fact wording refers to flooding from a natural weather event. It does not mention burst pipes or sewer overflows, and it sets no bacteria level. Swab results record what remains on surfaces either way. This is general information, not legal advice.
What does NSW Health say about floodwater in Sydney homes?
NSW Health warns that floodwater and leftover debris may be contaminated with sewage and that contact should be kept to a minimum. It also says to check walls and floor cavities for trapped water or mud, because mould or mildew may develop if items are not completely dried.
How high did the 2022 Hawkesbury-Nepean floods reach at Windsor?
Infrastructure NSW reports that the March 2022 flood was 0.9 m higher than March 2021 at Windsor, the highest there since 1978. The July 2022 flood was 1.0 m higher than March 2021 at Windsor. Owners in flood-affected parts of Greater Sydney often ask what remains afterwards.
When should bacteria samples be taken in a Sydney apartment after sewage?
Two rounds tell you most. Sampling before cleaning documents the contamination, and sampling afterwards shows what remains. If only one round is possible, the round after cleaning is the one that shows what remains. Tell us about any strata or tenancy deadline when you first get in touch.
Who analyses bacteria swabs from Sydney properties?
A laboratory analyses the swabs, not Test Australia. The report names the laboratory and states any accreditation that applies. Test Australia itself is not NATA-accredited. Suitably qualified occupational hygienists collect the samples and record site conditions, and the signed report states the criteria each result is compared with.
Can a Sydney bacteria report help in a strata or insurance dispute?
It records where contamination was found, where it was not and, where this can be seen, where the water came from. That helps a owners corporation, a lot owner and an insurer work from the same facts. Whether a tribunal, court or insurer relies on it is a decision for them.
Does Test Australia clean sewage-affected homes in Sydney?
No. Test Australia tests and reports only. It does not clean, disinfect or recommend anyone who does, and it takes no referral income. That keeps the swab results before and after the work independent of whoever carries out the clean, whichever party engages us.