If you suddenly start smelling foul odors in your yard, your septic tank may have collapsed. A collapsed septic tank is a serious emergency since it will block the contents of the tank from exiting into your septic system's drainfield — wastewater you flush down the drain will either collect in your yard or start backing up into your home. If you think that your septic tank may have collapsed, read on to find out how it may have happened, the signs of a collapsed septic tank, and how you should fix the problem.
What Causes Septic Tanks to Collapse?
One reason that may cause a septic tank to collapse is driving a vehicle over it. The weight of the vehicle combined with the weight of the soil on top of the tank can crack it. The collapse may not be immediate, but a cracked septic tank is more likely to collapse in the future.
Since septic tanks are buried underground, they're exposed to hydrostatic pressure. When water saturates the soil and causes it to swell, the expanding soil creates pressure on the sides of the septic tank. A high water table in the area can also cause the soil underneath the septic tank to expand, which will push upwards on it. When a septic tank is cracked, all of this pressure can widen the crack until the tank splits apart entirely and collapses.
Septic tanks can also collapse due to age. Older concrete septic tanks are particularly susceptible to this, since the bacteria in the tank that eat the solid waste release hydrogen sulfide gas. Hydrogen sulfide will corrode concrete, making it weaker and more prone to cracking apart when exposed to hydrostatic pressure and the weight of the soil above it.
What Are the Signs of a Collapsed Septic Tank?
The most obvious sign of a collapsed septic tank is a foul smell in your yard. The collapse will bring some of the soil down into the tank, exposing the contents of the tank to the open air. In addition to the waste inside the tank, you'll also smell the noxious gases made by bacteria in the tank like methane and hydrogen sulfide.
If you continue to use the water in the home when your septic tank has collapsed, waste will eventually start backing up into your home's plumbing. A collapsed tank will block wastewater from exiting into your septic system's drainfield, so it will eventually start traveling back up your pipes once you've overloaded your tank.
What Should You Do When You Think Your Septic Tank Has Collapsed?
If you think that your home's septic tank has collapsed, stop using the water in your home and call an emergency septic system service. If you have appliances like a water softener or a refrigerator that draw water into your plumbing and flush it automatically, turn them off or turn off the main water supply to your house. Stopping any wastewater from entering the collapsed tank will prevent it from backing up into your home.
An emergency septic system service will inspect your tank and determine the extent of the damage. The collapsed tank will need to be replaced, and the inlet and outlet pipes may need to be replaced as well if they were crushed by the top of the collapsing tank falling on them. An emergency septic system service will be able to come to your home and replace all of the damaged components in your septic system as soon as possible, which will allow you to use the water in your home again.