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Can Rain Back Up A Septic System?

By 23 June 2020January 6th, 2023Winnipeg plumbers



That answer wouldn’t make for a very fun blog post though, would it?


Rain can back up a septic system, but understanding why and what you can do about it are two much more  interesting questions. Let’s start by taking a look at how septic tanks work:


Septic tanks take advantage of a wide variety of natural processes in order to eliminate solid waste. Liquid wastewater is then distributed through pipes into your drain field, where natural filtration and bacteria clean the water. This process is why rain can backup your septic system. When your drain field’s soil is already saturated with water from the rain, the wastewater has nowhere to go; it continues to sit in the septic tank. Should you continue to use water in your home, you may exceed the septic tank’s capacity, which can result in sewer backups.


What can you do about it? During a heavy rain, not much. Avoid using water as best as you can; no showering, no washing machines, no Slip ‘n’ Slide parties. You might also reorient drainage from your roof away from the drain field. Some septic tanks have a transfer pump to move wastewater into their fields; if you have one, turn it off if you’re sure the field is flooded. When the pump can’t drain the tank, it’s working for no reason, which can seriously hurt its lifespan.


The real trick is making sure your septic system is working properly before a heavy rain hits. A septic tank of sufficient capacity should be able to get you through a rainstorm, provided the rain isn’t ridiculously heavy and you’ve been maintaining the septic tank properly. You should be aware that when your septic tank seems to be backing up during any amount of rainfall, you could very well be having problems with your drain field. Fixing a drain field is dreadful work, and can take months – you want to avoid it if you can. That’s why it’s important to be mindful of your water usage, what you flush,  and the capacity of your septic system.


Are you worried that heavy rainfall and backup have damaged your septic system? Are you experiencing sewer backup? Don’t, under any circumstances, attempt to repair the septic tank yourself. Septic systems are quite complex, and DIY is dangerous unless you’re a professional plumber (and most professional plumbers know very well that rain can block a septic system). We offer septic tank services in Winnipeg and the surrounding area. While we don’t necessarily recommend calling us if you experience slow drainage during a deluge (that’s pretty typical), if you’re experiencing backups frequently or you’re worried about damage, give Clean Line a call. 

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