If your septic system is in good operating shape and properly sized for your property, it won’t normally give off foul odors. However, any lapse in maintenance or damage to your septic system can cause those pungent gases to gather inside or outside. A slight odor is normal around the septic tank itself, but if you’re detecting those odors inside, or if the odors are difficult to tolerate, there’s likely a problem that needs to be addressed by a professional septic system maintenance company.
What Causes Septic System Odors Inside a Home or Business?
When septic system odors are present indoors, it usually has to do with your drains or venting system. Specifically, here’s where indoor septic system odors may be coming from:
- Failed or dried plumbing traps – Plumbing traps are built into every sink, toilet and tub drain and are responsible for keeping septic gases from flowing back into the building. These traps are shaped with a curve, so they always hold onto a small amount of water (which provides a tight seal against gas).
If one of these plumbing traps fails or dries out from lack of use, the seal will fail along with it and allow septic gases back into the building.
- Blocked or damaged vent pipes – Vent pipes connect the plumbing elements in the building (sinks, toilets, tubs) to exterior-facing vents that expel sewer gases. Every time wastewater is ejected from the building (like flushing a toilet), it pushes air out with it. The vent stack carries this foul-smelling gas out and replaces it with fresh air.
If any part of the vent stack is damaged, it will keep these sewer gases inside the building, along with their odors.
- Drain line blockages – The drain line is part of the same plumbing network that’s connected to the vent stack but is responsible for carrying wastewater from plumbing elements to the septic tank.
If these drain lines are damaged or clogged, it can cause odorous gases to escape into the building.
- Seal failure around the toilet base – Toilets are sealed along their base with a layer of wax. This wax seal prevents sewer gases from penetrating through the floor and causing odors inside.
Over time, this wax seal may deteriorate or may be damaged if the toilet is moved. If so, it will open up a weak spot for septic odors to creep through.
- Leaking or cracked pipes – If septic system odors are localized inside the building, it may be due to a localized issue with your plumbing. For example, a cracked or leaking pipe may allow wastewater and gases to slowly accumulate inside the building and cause odors.
What Causes Septic System Odors Outside a Home or Business?
If septic system odors are present outside (but aren’t as noticeable inside), it usually points to an issue with the septic tank itself, or with exterior drainage components. Here are some of the most common reasons for septic odors outdoors:
- Overly full or clogged septic tank – Septic tanks are the central element in every septic system, so if you detect septic odors outside, there’s a good chance it’s due to an issue with the tank.
One of the most common odor causing problems is a clogged septic tank. Septic tank clogs can be due to poor quality effluent, high-volume usage or, most often, a septic tank that’s too full. It’s important to pump out the septic tank every few years, as this prevents septic odors from building up inside the tank and eventually escaping. - A damaged or poorly maintained septic tank – In that same vein, if the septic tank is damaged to the point of rupturing, it will allow septic gases to escape from the system. This is most likely to happen when a septic tank isn’t inspected and maintained regularly.
- An improperly designed or installed septic system – Septic tanks must be sized and located on the property using best practices. For example, they must be installed at sufficient depth and inside of stable soils. Further, the septic tank must be large enough to handle expected wastewater volumes.
If either of these aren’t handled properly, it will lead to a poorly functioning septic system that produces foul odors. - Saturated drain field – The other major failure point for septic systems is the drain field. This is where treated effluent goes once it’s ejected from the septic tank.
Drain field clogs are common, and when those clogs occur, it can cause septic gases to build up and gather outside the property. Drain field clogs are often caused by poor quality effluent or excessive wastewater volumes. - Damaged septic tank risers – Septic system risers allow for access and easy maintenance by connecting the underground septic elements to the surface. However, if these risers are damaged or don’t fit properly, septic gases will vent at ground level and cause odors.
- Heavy rains or high groundwater levels – When the drain field is saturated by heavy rains or by elevated groundwater levels, it forces septic gases upwards and can cause septic odors. That’s why odors are often detected after a storm.
Eliminate Septic System Odors with Expert, On-Time Maintenance
The occasional septic system odor isn’t necessarily a cause for concern, especially after a heavy rain. However, if those odors are constant or severe, it merits a deeper inspection into your septic system’s performance. The problem could be a damaged drain or vent pipe indoors, for example. Septic odors outside could mean a ruptured septic tank or an overly saturated drain field, for instance.
Regardless of what’s causing your septic system odors, the only sure way to resolve them is with expert septic system maintenance. An experienced septic technician can troubleshoot the source of those odors and recommend the right fix to restore your septic system’s performance.
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