Can A Septic Tank Explode?

You might be wondering if septic tanks can explode. Although they’re generally safe and reliable, there have been a few incidents of explosions.

In this blog post, we’ll explore the causes of septic tank explosions and how to prevent them. That way, you can keep your septic system safe and efficient.

So, what makes septic tanks explode?

Flammable gases building up (methane, hydrogen sulfide)

Septic tank explosions usually happen when flammable gases like methane and hydrogen sulfide build up inside the tank. These gases are natural by-products of wastewater decomposition.

While methane is highly flammable, hydrogen sulfide is toxic and can be deadly in high amounts. Normally, these gases safely vent into the air, but if the tank or venting system isn’t working right, they can accumulate to dangerous levels.

Ignition sources that can cause explosions

A few ignition sources can set off a septic tank explosion when there’s a high concentration of flammable gases. Some common sources are:

Open flames: Welding or using a torch near the tank can ignite gases and cause an explosion.

Electrical sparks: Electrical equipment like pumps or switches can create sparks that ignite flammable gases. Make sure electrical connections and components are properly sealed and maintained.

Static electricity: Friction can cause static electricity, creating a spark that ignites gases. Avoid rubbing or dragging objects (like plastic pipes) near the tank.

Smoking near the tank: Tossing a lit cigarette or smoking near the tank can ignite trapped gases, potentially causing an explosion.

Real-life septic tank explosions

Although rare, septic tank explosions do happen and can cause severe property damage or even death. In 2016, a family from Zephyrhills, Florida, claimed they had a close call when their septic tank caught fire and blew up.

Luckily they managed to escape their home in time. This is the video from ABC Action News.

In Port Charlotte, Florida, a lightning strike hit a septic tank, resulting in an explosion that caused a toilet in the home to shatter.

This is the video which includes an interview with the homeowner.

How to tell if your septic tank is at risk

It’s crucial to spot warning signs that your septic tank might be at risk, so you can prevent explosions and keep your system safe and efficient. Keep an eye out for these signs and, if necessary, get professional help.

Bad smells around the tank area

If you notice a strong, nasty odor around your septic tank or drain field, your system might not be working right. This could be due to a build-up of flammable gases or a venting problem. Inspect and maintain your tank ASAP to avoid risks.

Fixtures drain slowly

If your sinks, tubs, or toilets are draining slowly, your septic tank might be full or there could be a pipe blockage. This can increase pressure in the tank and could lead to an explosion if trapped gases find an ignition source.

The plumbing system makes gurgling sounds

Weird gurgling noises from your plumbing can signal a problem with your septic tank. This might be due to a blockage, poor venting, or a full tank. These issues can cause pressure and gas build-up, raising the risk of an explosion.

Wet soil around the tank or drain field

Soggy or wet soil around your septic tank or drain field might mean there’s a leak or overflow. This can release untreated wastewater and cause flammable gases to accumulate.

Not only is this a risk for explosions, but it can also contaminate the area and create health hazards. Act quickly to find the cause and fix the problem.

How to prevent septic tank explosions

Keeping your family, property, and the environment safe means taking steps to prevent septic tank explosions. Here’s what you can do to minimize the risk:

Inspect and maintain your tank regularly

Inspection and pumping frequency: Inspect your septic tank every 1-3 years and pump it every 3-5 years, depending on the tank size and your household size. This prevents flammable gas build-up and keeps your system working well.

Spot and fix leaks: During inspections, watch for leaks or damage to the tank, pipes, or venting system. Fixing issues quickly can help stop flammable gas accumulation and reduce explosion risk.

Make sure your tank is vented properly

Why venting matters: Venting is crucial for septic tank safety since it lets flammable gases escape and stops them from building up in the system. Check that your tank is vented well and vents are clear.

Checking for venting problems: Inspect vent pipes for blockages like debris or bird nests. Also, verify that the vent pipe height and location meet local regulations for proper gas dispersion. If you find venting issues, get a professional’s help.

Teach your family about septic tank safety

No smoking near the tank: Make sure everyone knows the dangers of smoking near the septic tank. Set up a no-smoking zone around the tank area to lower the risk of igniting flammable gases.

Keep open flames and electrical sources away: Teach your family about the risks of using open flames or electrical equipment near the tank, like welding or using power tools. Keep a safe distance between the tank and potential ignition sources.

Get professional help when needed

When to call an expert: If you spot signs of a malfunctioning septic tank or suspect venting issues, call a professional. Trying to fix it yourself can be risky and may cause more damage.

Choose the right service provider: Pick a reputable, experienced septic tank service provider for inspections, maintenance, and repairs. Look for proper licensing, insurance, and positive customer reviews to ensure they deliver quality service.


Septic tank explosions are rare but may occur when flammable gases accumulate and encounter ignition sources. Identifying warning signs and taking preventative measures can ensure your system’s safety.

Regular maintenance, proper venting, and educating your family about safety are crucial to reducing risks. By following these steps and seeking professional help when necessary, you can prevent explosions and maintain a secure home.

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