Rodent Control for Septic System Drainfields
Many septic system owners are aware that there’s a number of things that can go wrong with their systems if they are not careful, as well as through unexpected conditions that are no fault of their own. However, one potential issue for septic systems that may not come to mind until they’ve experienced it is rodent damage.
Rodents that find access to a system might cause leaks by chewing through tank covers or pipes, disrupt drainage by burrowing into the drainfield, or cause backups and blockages in the system if they get into the lines or pipes.
Anyone who has ever seen a video of a rat in a sewer or a city subway tunnel probably won’t be that surprised that rats may be drawn to the contents of a septic tank or start chewing into a system. However, they’re not the only ones capable of doing damage! While they are much smaller in size, mice can do much of the same damage that rats can. And though they are not technically rodents but merely similarly burrowing creatures, moles and mongooses have also been found to damage septic systems.
Other common rodents or similar creatures known to burrow in yards in North America to keep an eye out for include: voles, prairie dogs, groundhogs, gophers, and chipmunks. If there’s visible damage to a yard/drainfield but the animal responsible hasn’t been spotted, an educated guess can be made by determining what digging creatures are in range and looking for signs of damage associated with possible candidates, as well as footprints and scat. Tunnels of varying depths, dirt holes and piles, and damaged plants/trees/crops are among common signs of rodent damage.
Rodent-Proof Construction
If a new or replacement system is going into an area with known burrowing rodent activity, one option to avert potential damage is to attempt to rodent-proof the construction of the system. Infiltrator Water Technologies recommends the installation of chicken wire in the trench under system chambers, especially for the prevention of damage from gophers.
Nebraska Extension, in their guide to rodent-proof construction for drains and feeding equipment, recommends that discharge pipes be secured so that rodents cannot enter them. System cleanout ports and risers should also be secured and not left with open holes for animals to climb into. Rodent shields for pipes, vent screens, or “floating” metal covers that open with the flow of water are options to secure pipes.
Strategies for Post-Installation Rodent Control
Once a system is installed in a rodent-prone area, there are steps that can be taken to help manage the likelihood of a problem. First is to mow regularly in order to ensure that signs of tunneling, burrowing, and digging are more easily spotted in and around the drainfield. This will also make it easier to spot some rodents in the middle of the soil treatment area.
If rodent burrow holes are discovered, it may be possible to fill them in with gravel if the infestation has not become too severe yet.
Regular inspection of the system is also necessary. While regular inspection should be done anyhow, the idea of rodents might scare some homeowners into actually committing to it! Aside from observing damage to the system, other signs of damage to a system that can be associated with rodents or other pests can include: strong odors if a system is leaking, slow draining fixtures if pipes are blocked, system alarms going off from damage to electrical components, and soft/soggy soil around a drainfield; if proper drainage was disrupted by burrowing rodents.
If a rodent problem is known, the most reliable way to fix it is to call in professional rodent/pest control services. Professionals will be best equipped to advise the best route to take for eliminating the pest. Ultimately, homeowners that find their systems damaged by rodents should likely be calling both their local septic professional and a pest control specialist right away. After any damage to the system is repaired by the septic professional and the current set of rodents are cleared by pest control, a long-term prevention plan should be developed and put in place.
What Not to Do
There’s also a few things worth highlighting as methods to avoid when it comes to rodent control for septic issues.
First; putting poison bait or traps underground within the drainfield has the potential to leach into the groundwater supply, ultimately contaminating it for all those who use it. The chemicals may also affect the ability of the soil’s microbiome to effectively filter the effluent leaving the septic system in the drainfield. In addition, rodents that ingest the poison may go on to die within the components of the drainfield or septic system, which could clog the drainfield and potentially lead to system backups and failures.
As mentioned above, regular mowing is advised so that it’s easier to see rodents or signs of rodents in a drainfield area. Many septic owners consider planting native flowers or grasses on their drainfield in order to take advantage of the soil’s nutrient-rich microbiome to boost plant growth. Unfortunately, doing so will also make it more difficult to spot rodents, and the native plants may even attract more of them by providing cover. Choosing to keep the drainfield as a well-mowed field of lawn grass is the best option to take when seeking to keep rodents away.
Finally, while we are on the topic of rodents and septic systems, there is a myth out there that flushing a dead mouse (or other small animal) down a toilet into a septic system is beneficial to a system. The idea is that the mouse carcass adds helpful microbes into a system. However, new microbes are added to a system every time a toilet is flushed, and in a properly functioning septic system, this is all it needs. So, if you encounter any homeowners wanting to flush rodents down their toilet, let them know that this simply is not necessary!
Sources & More Information
- How to Stop Drain-Loving Rats from Getting into Your Property | Martins Pumping Service
- Can Burrowing Animals Damage Your Septic System? | Maui Pumping
- How Pests Can Wreak Havoc on Your Septic System | Speidel & Sons Septic Service
- Rodent-Proof Construction: Drains and Feeding Equipment | University of Nebraska Extension
- Prairie Dogs and Their Control | University of Nebraska Extension
- Controlling Nuisance Moles | University of Missouri Extension
- Moles in the lawn | Michigan State University Extension
- Animals Digging in Lawns | Animals Digging in Lawns
- How to Identify Rodents in Your Yard | TruTech Wildlife Service
- How to Modify Habitat to Discourage Nuisance Wildlife in Your Yard | University of Florida Extension
- 5 Top Myths About Septic Systems | Family Handyman