When a property is affected by sewage backflow or black water flooding, the consequences extend far beyond a foul smell or visible mess. While the temptation may be to disinfect the surface and move on, this can be a serious mistake. Sewage contains harmful pathogens, bacteria, viruses, and contaminants that can remain embedded in porous materials long after visible waste has been removed—posing significant health risks to anyone in the building.
In this article, we break down why sewage damage is dangerous, why standard cleaning isn’t enough, and what a proper sewage clean-up process looks like according to industry standards.
What Makes Sewage So Dangerous?
Sewage water—classified as Category 3 (Black Water) under the ANSI/IICRC S500 Standard—is considered grossly contaminated. It may contain:
- Pathogenic bacteria (e.g. E. coli, Salmonella)
- Viruses (e.g. Hepatitis A, Norovirus, Rotavirus)
- Parasites and protozoa
- Toxic organic matter
- Harmful gases like methane or hydrogen sulfide
Contact with sewage—through skin, inhalation, or ingestion—can lead to serious illness, including gastrointestinal infections, respiratory complications, and skin rashes. Children, elderly individuals, and people with compromised immune systems are especially vulnerable.
Why Surface Cleaning Isn’t Enough
One of the biggest misconceptions is that bleach or disinfectant can “solve” a sewage problem. While these products may remove visible signs and reduce surface-level bacteria, they cannot:
- Penetrate porous materials (like plasterboard, carpet, underlay, timber)
- Eliminate all pathogens embedded deep in subfloors or wall cavities
- Prevent microbial regrowth in hidden areas
- Neutralize contaminated air or odour at a microbiological level
Without professional restoration, contaminants can linger unseen, turning your property into a silent health hazard.
Proper Sewage Clean-Up: What the Process Should Look Like
According to the IICRC S500 Standard, any water damage involving sewage must be treated with specialty procedures, containment, and verification. At Reztor Restoration, our sewage clean-up process involves:
🔸 1. Hazard Identification and Safety Protocols
- Isolate the affected area using containment and signage
- Ensure technicians wear full PPE including respirators, gloves, boots, and suits
- Identify electrical or structural risks before entry
🔸 2. Extraction and Removal
- Extract standing sewage using commercial-grade vacuum systems
- Remove and dispose of porous materials that cannot be decontaminated (e.g. carpet, underlay, insulation, plasterboard below the flood line)
🔸 3. Cleaning and Antimicrobial Treatment
- Thorough clean of remaining surfaces using detergent-based products
- Apply hospital-grade antimicrobials to all exposed areas
- Treat adjoining rooms to prevent cross-contamination
🔸 4. Drying and Dehumidification
- Install drying equipment to prevent further microbial growth
- Maintain negative air pressure to isolate the work zone
- Monitor moisture levels to ensure safe drying
🔸 5. Post-Remediation Verification
- Final inspection using moisture meters and odour assessment
- Optional third-party clearance testing (if required for sensitive environments)
This is not just “cleaning”—it’s restoration, designed to eliminate unseen health risks and return the space to a sanitary, insurable condition.
Real Consequences of Poor Sewage Restoration
We've seen cases where well-meaning owners or trades simply cleaned and deodorized after a toilet overflow—only to have tenants report illness weeks later. In one instance, sewage had wicked up into wall cavities and under cabinetry, spreading contamination far beyond the visible area.
Improper restoration not only compromises health—it can also lead to:
- Insurance claim rejection due to inadequate response
- Mould growth requiring full remediation
- Legal exposure if occupants suffer illness or injury
- Ongoing odours and biohazard risk
Don’t Take the Risk—Trust Certified Sewage Restoration Experts
If you’re dealing with sewage damage, it’s critical to engage professionals trained in Category 3 response protocols. Surface-level cleaning simply isn’t enough to protect your health, property, or liability.
To learn more about the correct approach to sewage clean-up and how we protect clients from long-term risk, visit Reztor Restoration’s Sewage Clean-Up Service.
About the Author
Daniel Brunes is Director of Reztor Restoration and Restoration Warehouse, and a certified Master Water, Fire and Mould Restorer. His team specializes in high-risk restoration, including sewage clean-up, structural drying, and insurance-compliant documentation across residential and commercial properties.
