Septic Tank Myth Buster

Household septic tank system

Can septic tanks blow up? And should you be worried about that brown patch of grass above your tank? In this myth-busting guide, we answer the most pressing septic tank questions.  

1) Is rain a problem for septic tanks?

As UK citizens, we’re all too familiar with rainy spells – but does rain affect our septic tanks? The answer is yes.    

Septic tanks rely on the surrounding drain field to filter out remaining bacteria from the wastewater, before distributing the filtered water evenly throughout the soil. Too much rain can overload this system, and restrict the drain field’s ability to release this liquid, resulting in excess water filling up in the septic tank.

Problems with your drains shortly after a bout of rainy weather could be caused by an overflowing or flooded tank. The best thing you can do to prevent this issue is to limit water usage during heavy rain and to consult with a drainage specialist if the problem persists.

2) Can septic tanks explode?

It may seem like the stuff of action movies, but the potential for septic tanks to explode is very real – that is, if their upkeep is neglected.

To prevent septic tank explosions, they will need to be well-ventilated. Due to the production of methane during the anaerobic digestion process, this gas can build up in the septic tank. Adequate ventilation should therefore be incorporated into the design from the very beginning, and professionals should install, repair and maintain your septic tank to ensure nothing is missed. You should also keep heat sources away from your septic tank, such as matches, cigarettes and electrical tools that produce sparks – especially when any manhole covers have been removed.

3) Do septic tanks kill grass?

Have you noticed the patch of grass above or around your septic tank turning brown or yellow? It may be alarming, but it’s actually a sign of a healthy septic tank.

Firstly, septic tanks don’t often kill grass outright, rather they simply cause the grass to go dormant for a while – especially in the summer months. Because the soil over your septic tank is not as deep as soil in the rest of your lawn, it has a more shallow area to absorb water from – therefore, it may not look as healthy or ‘green’. The temptation may be to water the grass. You should resist, as this could affect the drain field’s ability to do its job and could have an adverse effect on your septic tank. Instead, if the issue continues to bother you, try adding some more topsoil to the area.

You should only seek professional help should the grass dormancy last long past summer, or if your grass does not revive.

4) What happens when septic tanks overflow?

Signs that your septic tank has reached full capacity and is overflowing, include:

  • Expanding on point three, grass that looks too healthy and green all year round may actually be a bad sign – indicating a septic tank that is leaching liquids, causing the grass to thrive.
  • Pooling water that is refusing to drain away. This is caused by the drain field pipes becoming clogged, whereby liquid will pool on the surface.
  • Strange or unpleasant odours could also be indicative of an overflow or blockage.
  • Slow drains in your property could be caused by a number of factors. First, try drain cleaner to see if it’s a more internal issue. If the problem persists, you may have a septic tank overflow situation on your hands.
  • Arranging for someone to come out and cast a professional eye over your septic tank is the only surefire way of determining if you have an issue.


Struggling with your septic tank? Here at Express Drainage Solutions, we provide comprehensive drainage and septic tank services to a wide area across London and beyond. If you need a reliable septic tank repair, servicing or installation – we have the expertise to help you. Get in touch to discover more.

Read More:

Septic Tanks: How Do They Work?

Top 5 Tips for Septic Tank Maintenance

Want more information?Contact us today on 020 3124 1785

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Category: Septic Tanks


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