Rat Holes in the Yard: How to Identify and Close Burrows

A rat hole is an opening a few inches wide with smooth, worn edges, usually tucked against a foundation, under a woodpile or shrub, or beside a garden or trash area. If rats are still using it, deal with the rats first, then fill the hole with sand or gravel and pack it down hard.

Start with location. UC IPM says Norway rat burrows turn up along building foundations, under piles of rubbish or wood, and around gardens and fields. NYC Health adds bushes, plants, clutter and garbage to the list, and notes the holes can show up in concrete as well as bare dirt.

Next, look for a second hole. NYC Health says a burrow often has both an entrance and an exit, so one opening rarely tells the whole story. Rats also reuse the same route over and over until it wears a visible path through the grass, and NYC Health lists those runways, along with greasy rub marks on walls, as telltale signs. For a fuller checklist, see the guide to signs of a rodent infestation.

It depends on which source you ask. ICWDM says Norway rat holes tend to be 2 to 3 inches wide, while NYC Health describes rat burrows as 1- to 4-inch holes.

Size alone won't settle it, so check the rim too. ICWDM notes that rat holes get worn smooth by constant traffic, and NYC Health also lists smooth edges. An opening that looks polished and packed tells you something passes through it often.

Then think about when you see the animals. ICWDM says rats are secretive and rarely show themselves during the day, so spotting them in daylight means a lot of rats are living on the property. One daytime sighting near a burrow is a sign the problem is bigger than a single hole.

Hole size, the edges and the animals you actually see will usually sort it out. Rat holes sit near cover and food with worn runways leading in, while voles, chipmunks and ground squirrels each leave a different pattern.

Voles dig smaller openings. UC IPM puts vole burrow openings at about 1-1/2 to 2 inches across, linked by a maze of runways on the surface of the lawn. A web of narrow trails joining several small holes points to voles before rats.

Chipmunk holes look neat. ICWDM describes them as cleanly dug and about the size of a large coin, and says chipmunks are easy to see during the day. That daytime visibility is a useful contrast, since rats keep out of sight in daylight.

Ground squirrels go bigger. UC IPM says California ground squirrel burrows measure about 4 inches across, and older entrances are sometimes much wider. Because NYC Health's range for rat holes also reaches 4 inches, the animals you see coming and going are a good tie-breaker.

The holes cluster where rats find shelter close to food. Woodpiles, junk piles, dense shrubs and vegetable beds give them cover right where they want to dig, so those are the first spots to clear and check.

Compost can draw them in as well. UC IPM says rats sometimes burrow under or around compost piles, and the odds go up when people add meat, fish, eggs or eggshells. Keep those scraps out of the pile, and check its base for new holes each time you add to it.

When you move wood or clear clutter, go slowly and look under each item for holes and runways. Wear gloves for this kind of yard work and wash your hands as soon as you finish, which NYC Health advises for gardening anywhere rats are active. Bag loose trash and keep garbage in bins with tight lids so the yard offers less to eat.

Yes, once the burrow is inactive. NYC Health's advice is to pack the hole with sand or gravel and tamp it down firmly.

So how do you know a hole is inactive? NYC Health counts a burrow with leaves or cobwebs over the opening as inactive. An opening that stays clean and smooth is still getting traffic, so handle the rats before you close it.

Here is how to close one. Pour sand or gravel into the hole, then pack it hard with the back of a shovel or your boot, or cave the tunnel in with the shovel blade. Check the spot again over the next few days, since a filled hole that opens back up tells you rats are still around.

Skip the shortcuts. NYC Health says a board, cinder block or rock laid over the opening will not keep rats out, and it warns against pushing broken glass or chemicals down the hole. UC IPM advises against smoke and gas cartridges near homes, because Norway rat tunnels can run under the house and have several openings, so the fumes can seep indoors.

Make the ground along the house hard to dig. ICWDM says a strip of heavy gravel next to the foundation will cut down on rat burrowing, using stones at least 1 inch in diameter. Lay the strip at least 2 feet wide and at least 6 inches deep.

Next, look up from the ground. A burrow pressed against the foundation is a good reason to check the wall above it for gaps around pipes, vents and siding, and the page on rodent entry points in a house lists where to look.

Then keep the yard boring for rats. Keep woodpiles and junk away from the foundation and trim back dense shrubs so the ground stays open. Clear ground also makes any new hole easy to spot on a quick walk around the house.

Some cities do. DC Health, for one, treats rat burrows and then covers them so children and small animals can't get at the chemical. Call 311 or your local health department to ask what your city offers.

Programs and rules differ from place to place. If anyone puts rat poison in your yard, it should go in tamper-resistant bait stations and be used exactly as the label says. NYC Health also says owners of multi-unit buildings there must hire a licensed pro for this work. That is the reason DC covers treated burrows: bait left open in a hole is within reach of kids and pets.

Call a pest pro if filled holes keep reopening, if you see rats out in daylight, or if burrows sit right against the house. Each of those points to more rats, or a deeper tunnel network, than a shovel and a bag of sand can handle.

A pro starts with an inspection of the whole property, not just the hole you found. Expect them to trace runways, map active burrows, and check the foundation, vents and utility lines for places where rats could move from the yard into the house. Ask whether the company is licensed in your state and what follow-up visits include.

From there the work is trapping and sealing. Trapping removes the rats, with bait in tamper-resistant stations only where it fits and only per the label. Sealing closes the gaps in the building, and the old burrows get filled and tamped so any new digging stands out. The page on professional rodent exclusion explains that sealing step in more depth.