Filling animal holes in your yard safely comes down to three things: knowing what dug the hole, choosing the right fill material, and making sure you are not breaking any wildlife laws in the process. Most small holes left by chipmunks, voles, or moles can be packed with topsoil and tamped firm in a few minutes. Larger burrows from groundhogs, gophers, or armadillos take more effort and a layered approach. But the “safely” in the question matters more than most people realize, both for the structural integrity of your lawn and for the animals themselves.
Figure Out What Made the Hole
Before you grab a shovel, spend a few minutes identifying the culprit. The size, shape, and location of the hole tell you a lot about what animal created it, how deep the tunnel system runs, and whether the animal is still living there. Filling an active burrow while the animal is inside is both inhumane and counterproductive, since many species will simply dig back out or create new entrances nearby.
Small holes about one to two inches across, often surrounded by a little mound of loose soil, typically belong to voles, chipmunks, or large insects like cicada killers. These are shallow and easy to fill. Holes in the two-to-three-inch range, especially in garden beds or near foundations, often come from rats or chipmunks with more established tunnel networks. Larger openings of four inches or more, sometimes with a fan of excavated dirt in front, usually point to groundhogs, gophers, or rabbits. Cone-shaped mounds of fine soil with no visible entrance hole are classic mole activity, where the tunnels run just below the surface.
If the hole edges look fresh and you see tracks, droppings, or freshly turned soil nearby, the animal is likely still using the burrow. Watch the hole for a day or two before filling. Stuff a loose wad of newspaper or a few leaves into the opening. If it gets pushed out overnight, the burrow is active. You will need to encourage the animal to leave before sealing things up, or the fill will not hold.
Check Whether the Animal Is Protected
This is the step most homeowners skip, and it can land you in real trouble. Many burrowing animals have legal protections at the state or federal level. In the United States, groundhogs and moles are generally not protected and can be managed freely by homeowners. But other species are a different story. Certain ground-nesting birds, burrowing owls, gopher tortoises, and some fox species are protected under state wildlife regulations or the federal Endangered Species Act. Filling their burrows can result in fines.
The issue extends well beyond rare species. In the United Kingdom, for instance, it is a criminal offense to interfere with a badger sett under the Protection of Badgers Act 1992. One documented case involved a prosecution after five out of twelve sett tunnels were filled with a slurry material, with investigators using ground-penetrating radar to confirm the fill extended one to five meters into the tunnels.
If you are unsure what animal created the burrow, contact your local wildlife agency or cooperative extension office before filling. In most U.S. states, the state department of natural resources maintains a list of protected species and can tell you quickly whether the animal in your yard requires special handling. This five-minute phone call can save you significant headaches.
Choosing the Right Fill Material
The material you use depends on the hole size, its depth, and what you want the surface to look like afterward. For most yard holes, you have a few solid options:
- Topsoil: The go-to choice for small to medium holes. It compacts well, supports grass regrowth, and blends into the surrounding lawn. Use a loam-based topsoil rather than pure sand or pure clay.
- Topsoil-gravel mix: For deeper holes or burrow systems where you need structural stability, fill the lower portion with clean gravel or crushed stone and top off with six to eight inches of topsoil. The gravel provides drainage and discourages re-excavation.
- Sand-soil blend: Useful in areas with heavy clay soil where pure topsoil tends to hold too much water. A roughly 70/30 mix of topsoil and coarse sand drains well and packs firmly.
- Expanding foam: Sometimes recommended for sealing deep tunnel systems, but use this cautiously. It does not decompose, makes future landscaping difficult, and if an animal is still inside the burrow, it is inhumane. Reserve foam for situations where you are sealing entry points around foundations, not for open-yard burrows.
Avoid filling holes with concrete, asphalt, or other rigid materials in the middle of your lawn. These create drainage problems and make it impossible to mow or maintain the area later. They also do not flex with the soil, so they can crack and leave voids underneath that attract new burrowing. Pure sand is another poor choice on its own because it does not compact well and washes out easily in rain.
The Filling Process Step by Step
For small holes under three inches wide, the process is simple. Tamp the loose soil at the bottom of the hole with a stick or the handle of a tool to collapse any shallow tunnels immediately below the surface. Fill with topsoil in two-inch layers, pressing each layer down firmly with your foot or a tamper. Overfill slightly, mounding about half an inch above the surrounding grade. The soil will settle over the next few weeks, especially after rain, and you want to avoid ending up with a depression.
For larger burrows with tunnel systems, the approach takes more care. Start by probing gently around the main entrance with a metal rod or dowel to get a sense of how deep and how far the tunnels extend. You are not trying to map the entire network, just to understand whether you are dealing with a shallow depression or a system that runs several feet underground.
If the tunnel runs deeper than about 18 inches, fill the bottom section with gravel first. Pour it in slowly and use a garden hose to wash it down into the tunnels. Then switch to your topsoil, again adding it in layers and tamping each one. Water the fill lightly between layers to help it settle and eliminate air pockets. Air pockets are the main reason fills fail. They collapse weeks later, leaving a sinkhole in your lawn that looks worse than the original hole.
For the top few inches, use the same topsoil that matches your lawn’s existing soil. Rake it level, seed with grass if needed, and water regularly for the first couple of weeks. If the area sinks after settling, add more topsoil and reseed. Most fills need at least one touch-up within the first month.
Why Fills Sometimes Collapse
If you have ever filled a hole only to find a new depression in the same spot a few weeks later, the problem is usually one of three things: the tunnel system was more extensive than you realized, you did not compact the fill enough, or the soil characteristics around the burrow are working against you.
Research on mammal burrow systems shows that soil ejected from burrows tends to have low bulk density and erodes readily. The loosened soil around a burrow entrance is fundamentally different from the compacted ground elsewhere in your yard. It holds water differently, drains differently, and settles unpredictably.
This is why tamping matters so much. You are not just filling a void; you are trying to bring the fill material up to roughly the same density as the surrounding undisturbed soil. Without that compaction, water flowing through the loose fill carries particles deeper into any remaining tunnel voids, and the surface gradually sinks.
For persistent problem spots where fills keep collapsing, the best approach is to excavate the area more broadly. Dig down to the depth of the tunnel system, remove all the loose disturbed soil, and rebuild from the bottom up with compacted layers. It is more work, but it solves the problem permanently rather than creating an annual maintenance chore.
Keeping Animals From Coming Back
A freshly filled hole is an invitation to dig. The loose soil is easier to excavate than the surrounding undisturbed ground, and if the conditions that attracted the animal in the first place have not changed, a new tenant will often move in. Filling holes without addressing the underlying attraction is like patching a leak without fixing the pipe.
Grubs are the most common draw for moles, skunks, and armadillos. If your lawn has a grub problem, treating for grubs with a biological control like milky spore or beneficial nematodes removes the food source. Chemical grub treatments work faster but need reapplication. Without grubs, moles lose interest in your yard within a few weeks.
Groundhogs and rabbits are attracted by food and cover. Overgrown areas near fences, sheds, or brush piles provide shelter, and vegetable gardens provide meals. Clearing brush away from structures, installing hardware cloth along fence lines at or below ground level, and fencing gardens with buried wire mesh all reduce the appeal. Burying the mesh at least 12 inches deep and angling the bottom outward in an L-shape is particularly effective against digging species.
For areas where you repeatedly get burrowing activity near a foundation or patio, consider installing an exclusion barrier. This is typically galvanized hardware cloth or welded wire mesh buried vertically along the structure’s perimeter to a depth of 18 to 24 inches. It does not harm animals but physically prevents them from tunneling alongside the structure where their burrows can cause the most damage.
Holes Near Foundations and Structures
A hole in the middle of your lawn is mostly a cosmetic and tripping concern. A hole next to your house foundation, porch, or retaining wall is a structural one. Burrowing animals that tunnel alongside foundations can undermine footings, create pathways for water infiltration, and accelerate erosion under slabs.
If you find burrow entrances within a few feet of your foundation, take the situation more seriously than a mid-lawn hole. Probe carefully to understand the tunnel direction. If it runs toward or under the structure, you may want a professional assessment before filling. Simply packing soil into a tunnel that has eroded a void under a concrete slab can make things worse if the fill does not reach and support the slab from below.
For foundation-adjacent fills, a lean concrete mix or flowable fill (a low-strength concrete that can be poured as a slurry) is sometimes the better choice. It flows into voids that soil cannot reach and provides actual structural support. This is one situation where rigid fill materials make sense, unlike in the middle of a lawn where they cause more problems than they solve. If the burrow system appears to run under a load-bearing structure, call a foundation repair specialist rather than attempting a DIY fill.
Mole Tunnels Are a Different Problem
Moles create a unique challenge because their tunnels are shallow, running just a few inches below the surface, and they cover a lot of ground. You will not see a single entrance hole so much as raised ridges of soil snaking across your lawn, plus the occasional volcano-shaped mound where they pushed soil to the surface.
For surface tunnels, the fix is not really “filling” in the traditional sense. Step firmly on the raised ridge to collapse the tunnel and compress the soil back down. Water the area lightly afterward to help it settle. If the mole is still active, it will re-raise the tunnel within a day or two, but consistently collapsing active runs discourages continued use of that pathway. Moles typically maintain a network of runs and abandon sections that keep getting disrupted.
The deeper mole tunnels, usually about eight to ten inches down, are the ones the animal uses as permanent highways between feeding areas. These are harder to find and harder to collapse by stepping. If you can locate them by probing, filling them with compacted soil is effective. But the real solution for chronic mole problems is almost always grub and insect control. Remove the food, and the moles relocate on their own within weeks.
The Ecological Value of Burrowing Animals
It is worth understanding that the animals digging up your yard are doing something ecologically useful, even if it does not feel that way when you twist an ankle in a groundhog hole. Burrowing mammals play meaningful roles in soil health. Their digging reduces soil compaction, increases water infiltration, promotes nutrient cycling, and supports microbial diversity in the soil.
Research on these so-called bioturbator mammals has found that their activity can improve plant recruitment, boost soil moisture, and even contribute to carbon storage in the ecosystems they inhabit. The concern among ecologists is that declining populations of burrowing mammals could trigger cascading effects through the ecosystems that depend on their digging activity.1Mammal Review. Ecosystem roles and conservation status of bioturbator mammals
None of this means you should let groundhogs undermine your porch or tolerate mole tunnels across your entire yard. But it does mean the goal should be management, not eradication. Encouraging burrowing animals to move to a different part of your property or to neighboring undeveloped land, rather than killing them, preserves the ecosystem services they provide while keeping your yard functional. In many cases, simple exclusion barriers and habitat modification accomplish exactly that, redirecting the animal’s activity to areas where it does some genuine good.
When to Call a Professional
Most small animal holes are straightforward DIY projects. But a few situations warrant professional help. If you find extensive tunneling near your home’s foundation, especially if you notice new cracks in walls or uneven floors inside, a foundation specialist should assess the damage before you fill anything. If you suspect the burrowing animal is a protected species, a licensed wildlife control operator knows the regulations and can handle removal legally. And if your yard has so many holes that filling them individually feels futile, a pest management professional can identify the root cause, whether that is a massive grub infestation, a drainage issue attracting certain species, or a habitat feature you have not considered, and address it systemically rather than hole by hole.
For anyone dealing with a snake hole, exercise particular caution. Many holes attributed to snakes were actually dug by rodents and later adopted by snakes. If you see a snake entering or exiting a burrow, do not attempt to fill it while the snake may be inside. In regions with venomous species, this is a job for a wildlife removal professional, full stop.