How to Get Rid of Bad Smells After a Septic Tank Overflow
A septic tank overflow is one of those household emergencies most people hope never to face. Yet, when it does happen, it brings with it more than just a bad smell. It can pose health risks, damage your garden, contaminate soil and water, and create an unpleasant environment for everyone nearby. The good news is that there are clear steps you can take to manage the immediate aftermath and restore your property. Even better, these steps can be carried out without resorting to harsh chemicals that harm the ecosystem.
At Bioglobe, we specialise in organic enzyme remediation — a natural way to break down pollutants, neutralise odours, and restore balance to contaminated soil and water. Our approach is not only effective, but it also respects the natural environment by working with biological processes rather than against them.
This article will guide you through what happens during a septic tank overflow, the potential consequences, and the practical solutions available. By the end, you will know what to do straight away, what longer-term steps are needed, and how enzyme-based treatments can safely restore your garden and protect your family.
The Problem: What Happens During a Septic Tank Overflow?
A septic tank is designed to collect and treat household wastewater. It works by separating solids from liquids, with heavier sludge settling at the bottom, oils and grease forming a scum layer on top, and relatively clear effluent flowing out into a drainage field for further natural treatment. When everything works as it should, the system is safe, discreet, and odour-free.
But problems can occur when:
- The tank has not been emptied for a long time and becomes overloaded.
- Drains and soakaway fields become blocked or saturated.
- Heavy rainfall or flooding causes groundwater to push back into the system.
- Structural faults (such as cracks in the tank or collapsed pipes) cause leaks.
When this happens, untreated or partially treated sewage escapes where it should not. You may notice:
- Pools of dirty water or sludge appearing on the surface of your lawn or garden.
- Toilets, sinks, and drains backing up indoors.
- A foul odour, sometimes described as rotten eggs or ammonia, drifting across your property.
- Soggy, foul-smelling soil around the tank or drainage field.
What you are experiencing is an uncontrolled release of raw sewage into the environment. This mixture contains organic matter, bacteria, viruses, parasites, and a cocktail of chemical residues from household cleaning products. The result is both unpleasant and potentially hazardous.
The Consequences: Why Septic Tank Overflows Are More Than Just Smelly
It can be tempting to see a septic overflow as simply a nuisance because of the smell. However, the consequences can be far more serious.
1. Health Risks
Raw sewage contains pathogens such as E. coli, Salmonella, and various viruses and parasites. These can cause stomach upsets, skin infections, and respiratory problems. Children and pets are particularly at risk because they are more likely to come into contact with contaminated soil or water. Inhaling gases like hydrogen sulphide and methane, even in small amounts, can also be harmful.
2. Soil Contamination
When sewage seeps into the soil, it does not simply disappear. Organic matter and nutrients accumulate, upsetting the natural microbial balance of the soil. Beneficial microbes that support healthy plants may be suppressed, while harmful bacteria can multiply. The soil structure itself can become waterlogged, compacted, and less able to support normal garden life.
3. Groundwater Pollution
If contamination sinks deeper, it can reach the groundwater. This is particularly concerning if you rely on a well for water, or if groundwater flows towards local streams or rivers. Nitrates and phosphates from sewage can fuel algae growth in water bodies, leading to oxygen depletion and harm to aquatic life.
4. Persistent Odours
Even after visible sewage has been cleared, the smell often lingers. That is because anaerobic bacteria in the soil continue breaking down waste, producing gases such as ammonia and hydrogen sulphide. Without proper remediation, these odours can persist for weeks or even months.
5. Legal and Social Consequences
Neighbours may complain, and local authorities may intervene if the overflow is significant or if it risks polluting watercourses. In some cases, property owners may be liable for clean-up costs or even face fines.
Clearly, septic overflows are more than a minor inconvenience. They are events that need immediate, thoughtful action.
The Solution: What to Do After a Septic Tank Overflow
Step 1: Protect Yourself and Your Family
Safety must come first. Avoid direct contact with contaminated water or soil. Wear protective gloves, waterproof boots, and, if odours are strong, a face mask. Keep children and pets away from the affected area until it has been remediated.
Step 2: Stop the Overflow if Possible
Reduce water use inside the house — avoid flushing toilets, running taps, or using washing machines. If the overflow is due to heavy rain, wait for the weather to ease before tackling the problem. If the tank is full, you may need to call a licensed waste disposal company to pump it out.
Step 3: Contain the Spread
If sewage is spreading across your garden, create barriers using sandbags, soil mounds, or absorbent pads. This prevents the contamination from reaching larger areas or flowing into watercourses.
Step 4: Remove Standing Sewage
Where safe, remove pools of contaminated water using pumps or absorbent material. This should be disposed of via a licensed waste service. Do not attempt to wash sewage into storm drains or nearby ditches, as this will spread contamination further.
Step 5: Assess the Extent of Damage
Examine the area carefully. Has sewage soaked into just a small patch of lawn, or has it spread widely? Is the soil heavily saturated, or has the overflow been relatively minor? For a proper assessment, soil and water samples can be analysed in a laboratory to detect pathogens and nutrient levels.
Step 6: Begin the Clean-Up
This is where many homeowners face a dilemma. Chemical disinfectants may seem like an easy fix, but they can leave residues, kill beneficial microbes, and harm plants. Instead, a more sustainable and effective approach is to use biological solutions that restore balance naturally.
The Role of Enzyme Remediation
Enzymes are natural proteins that speed up chemical reactions. In the context of sewage contamination, specific enzymes can break down organic matter — proteins, fats, starches, and fibres — into simpler substances that are less harmful and easier for beneficial microbes to digest.
For example:
- Proteases break down proteins from human waste and food scraps.
- Lipases break down fats and oils.
- Cellulases help decompose plant fibres and paper.
- Amylases break down starches from household waste.
By applying the right mix of enzymes to contaminated soil, the sewage is effectively digested and neutralised. As complex waste molecules are broken down, odours are eliminated, and conditions become less favourable for harmful bacteria.
At Bioglobe, we take this a step further by analysing the exact pollutants present in each case and creating bespoke enzyme blends. This ensures the treatment is highly effective and targeted, rather than relying on generic products that may only partially address the problem.
Why Enzyme Treatments Are Better Than Chemicals
- Eco-Friendly: Enzymes are biodegradable. They break down naturally and do not leave harmful residues.
- Safe for Soil and Plants: Instead of sterilising the soil, enzymes restore balance and support healthy microbial activity.
- Odour Control: By breaking down waste at the molecular level, enzymes tackle the root cause of bad smells rather than just masking them.
- Long-Term Benefits: Regular maintenance treatments can help keep septic systems and soil healthy, reducing the risk of future overflows.
Bioglobe’s Approach
At Bioglobe, we combine scientific expertise with practical remediation. Here’s how we help:
- Pollutant Analysis: We test soil and water samples to identify what contaminants are present.
- Custom Solutions: We design enzyme blends specifically for your contamination, ensuring maximum effectiveness.
- Safe Application: We use methods such as soil injection or surface irrigation, depending on conditions.
- Ongoing Monitoring: We can re-test the soil after treatment to ensure it is safe and odour-free.
- Sustainable Outcomes: Our treatments not only solve the immediate problem but also help restore natural balance.
Preventing Future Overflows
While enzyme treatments can help restore your garden after an overflow, prevention is always better than cure. Here are some tips:
- Have your septic tank inspected and pumped regularly.
- Avoid flushing items that do not decompose easily, such as wipes or sanitary products.
- Spread out water use in the home to avoid overloading the system.
- Keep an eye on your drainage field for signs of saturation, such as unusually green patches of grass or soggy soil.
- Use enzyme maintenance treatments periodically to keep the system healthy.
FAQs
Is septic tank overflow dangerous to health?
Yes. It contains bacteria, viruses, and parasites that can cause illness. Exposure should be avoided until the area has been properly remediated.
Can enzymes disinfect the soil after overflow?
Enzymes do not act like bleach or disinfectants. Instead, they break down waste into harmless substances, removing the food source for harmful microbes. This creates conditions where the soil can recover naturally, and harmful bacteria decline over time.
How long until my garden is safe again?
This depends on the severity of the overflow. With professional remediation, odours may disappear within days, while full recovery of the soil can take a few weeks to a few months. Testing can confirm when it is safe.
Do I need professional help, or can I treat it myself?
Minor overflows can be managed with basic clean-up and off-the-shelf enzyme products, but for significant contamination, professional expertise is strongly recommended. Bespoke solutions are far more effective than general treatments.
Can enzyme treatments stop future overflows?
Enzymes cannot fix mechanical failures or prevent flooding, but they can help maintain a healthy microbial balance in the system. This reduces the risk of blockages and odour problems in the future.
Conclusion
A septic tank overflow is unpleasant, stressful, and potentially hazardous. But by acting quickly and using the right solutions, you can protect your family, restore your garden, and prevent lasting damage. Chemical disinfectants may appear to offer a quick fix, but they can do more harm than good. Enzyme treatments provide a natural, eco-friendly, and effective alternative that deals with both odours and contamination at their source.
Bioglobe is here to support you through this process. From testing and analysis to bespoke enzyme solutions, we offer a safe and sustainable way to reclaim your garden and restore peace of mind.
Bioglobe offer Organic Enzyme pollution remediation for major oil-spills, oceans and coastal waters, marinas and inland water, sewage and nitrate remediation and agriculture and brown-field sites, throughout the UK and Europe.
We have created our own Enzyme based bioremediation in our own laboratory in Cyprus and we are able to create bespoke variants for maximum efficacy.
Our team are able to identify the pollution, we then assess the problem, conduct site tests and send samples to our lab where we can create a bespoke variant, we then conduct a pilot test and proceed from there.
Our Enzyme solutions are available around the world, remediation pollution organically without any harm to the ecosystem.
For further information:
BioGlobe LTD (UK),
Phone: +44(0) 116 4736303| Email: info@bioglobe.co.uk