Can Moles Swim? What Flooding and Rain Do to Them

Yes, moles can swim. Most species are land animals that swim only when they have to, for example to cross a creek, a ditch or a flooded patch of ground, and the star-nosed mole is a true semi-aquatic specialist that hunts underwater. That also explains why a garden hose rarely drowns a mole. It has a tunnel system to retreat into, and it is a better swimmer than most people assume.

TL;DR

• Moles can swim. Most do it only out of necessity, and the star-nosed mole does it for a living.
• Rain and flooded tunnels rarely drown a mole. It moves to drier or deeper sections of its tunnel system.
• Running a hose into the tunnels is almost never effective and can pull more earthworms toward the surface.
• Mulch, compost and heavy irrigation feed moles by raising worm numbers, so they influence where moles settle.
• Trapping in an active runway is the method that actually removes the mole causing the damage.

Table of Contents

• How well can moles swim?
• Do moles drown when it rains?
• Why flooding tunnels does not work
• Can moles live in mulch?
• How to tell if you have a mole problem
• What does work: trapping in an active runway
• Our perspective: why we trap and don’t flood
• When to call a professional
• FAQ
• Sources

How well can moles swim?

A mole’s body is built for digging: wide front feet, strong claws, a cylinder-shaped torso and dense velvety fur. None of that looks like swimming gear, yet a 1984 study of talpid moles concluded that terrestrial moles are good swimmers, apparently thanks to their small size and their fur. Small bodies with trapped air in the coat float well.

In practice, a common backyard mole, such as the eastern mole found across the eastern half of the US, will paddle across a small obstacle if it meets one. It does not choose to hang around in open water. Think of swimming as an emergency skill: useful when a tunnel floods or a creek bank blocks the way, but not part of daily life.

The star-nosed mole is the exception

The star-nosed mole lives in wet ground in the northeastern US and parts of Canada. The Natural History Museum explains that it can forage for prey underwater, and that it can even “sniff” underwater by blowing and re-inhaling scent-carrying air bubbles. Its forepaws make alternate strokes through the water, which gives it a zigzag swimming pattern.

Even this species does not live entirely in water. According to the SUNY ESF Adirondack Ecological Center, star-nosed moles living near water get only 12 to 25 percent of their food from the soil layers, taking the rest from aquatic sources. It is the one mole you would expect to see in a stream, and it is not the one chewing up most American lawns.

Do moles drown when it rains?

Occasionally a mole is caught out, but heavy rain is not a reliable mole killer. A mole’s tunnels are a network, not a single dead-end pipe. When the shallow feeding tunnels near the surface soak through, the animal moves into deeper tunnels or toward higher, drier ground. Moles are active year-round, and Washington Department of Fish & Wildlife notes that they are active at any time of day, so a wet season does not shut them down.

What rain does change is where you see damage. Worms move in wet soil, and moles follow them. After a rainy week in Oregon or Washington, a lawn that looked fine can suddenly show fresh ridges and mounds. That is not a new invasion. It is the same mole, working the surface layer where food is now easier to reach.

What about a mole found floating in a pool?

A mole in a swimming pool has usually fallen in while crossing the yard. Its dense coat keeps it afloat for a while, but smooth pool walls give it no way out, and it can tire. If you find one, avoid handling it with bare hands, because any wild mammal can bite when frightened. Lay a ramp, such as a board or a mesh net with a rough surface, against the pool edge so it can climb out on its own. If it is injured, call a licensed wildlife rehabilitator or your state wildlife agency.

Why flooding tunnels does not work

This is the part that costs homeowners the most time. The idea sounds logical: moles are not aquatic, so fill the tunnel and they will drown or run. Extension specialists say otherwise. The University of California’s IPM program states that flooding tunnels is typically ineffective and wastes water, because moles have extensive burrow systems that take a great deal of water to fill.

There are four reasons it fails.

1. The network is large. A hose can run for hours and the water drains into soil, side tunnels and deeper galleries rather than filling one chamber.
2. The mole leaves. It has the whole system to retreat into, and if one section floods, it relocates.
3. Worms rise. Saturated soil pushes earthworms up, which is exactly the food the mole wants. Water can end up attracting more prey to the surface and increasing activity instead of reducing it.
4. The lawn pays. Soggy turf, washed-out soil and a bigger water bill make the damage worse, not better.

Wildlife management experts quoted in the Missouri Extension guidance make a broader point: moles lead specialized, established underground lives, so shortcuts like flooding and repellents rarely solve the problem. Removing the specific animal doing the damage is what produces long-term relief.

Can moles live in mulch?

Moles do not live in mulch the way a chipmunk might nest in a woodpile. They live in the soil below it. But thick mulch, compost piles and soft, peat-amended flower beds are attractive to them for a simple reason: they are rich in worms and soil insects.

The Tennessee Home and Farm guide explains that moles are driven by food, and that heavy mulching, compost piles and excess irrigation keep soil moist and organic matter high, which supports the prey moles need. Purdue’s extension specialist adds that replacing organic bark mulch with crushed stone or pea gravel around building foundations can make the area less appealing for burrowing and worm hunting.

Habitat changes are worth making, but be realistic about them. They are a preventive step, not a cure for an active problem. If a mole is already working your yard, changing the mulch will not remove it.

How to tell if you have a mole problem

Moles are rarely seen. You find them by what they leave behind. Mole mounds are the volcano-shaped piles of soil pushed up along tunnels, and surface ridges show where the animal has been feeding just under the turf. The Tennessee guide describes two kinds of runways: shallow feeding tunnels that appear as raised ridges, and deeper runs that connect the animal’s feeding areas and nest.

That difference matters, because the feeding ridges are often used once. The deeper, straight runways are used again and again, and that is where traps belong.

The damage also looks worse than the population really is. A University of Wisconsin publication on mole ecology notes that a high mole density is only 3 to 5 adults per acre. One or two active moles can produce an alarming network of tunnels in a few weeks. So a yard full of ridges does not mean you need to fight dozens of animals. It usually means a small number of animals need to be found and removed.

Moles can also be confused with other animals. Pocket gophers, which are present in Oregon, make fan-shaped mounds, and voles use surface runways in grass. Getting the animal right decides which approach works, which is why identification comes first.

What does work: trapping in an active runway

The practical method with the best track record is trapping. Missouri Extension explains that because moles instinctively reopen blocked passages, you can find an active runway by flattening a section of tunnel and seeing whether it is re-excavated within 24 hours. A trap set in that active run takes advantage of the same instinct, and a correctly placed trap typically produces a result within 24 to 36 hours.

Clemson’s Home & Garden Information Center likewise points to harpoon-style traps, and adds that they must be set a particular way over the mole run to be effective. In other words, the trap is simple, but the placement is where people fail.

Poison baits are not a safe shortcut either. The University of Arkansas Extension notes that in that state toxic baits are ineffective and illegal, and rules for wildlife control vary by state. Check your own state wildlife agency before using any product on a mole.

Common trapping mistakes

• Setting traps in a meandering surface ridge that the mole has already abandoned.
• Pressing the tunnel down too much or too little, so the mole detects something unusual and digs around it.
• Leaving human scent on the trap or on the soil.
• Giving up after a single night instead of checking the runway again.
• Treating one mole and ignoring the next one moving in from a neighboring yard.

Our perspective: why we trap and don’t flood

We only deal with moles. In Oregon, we also handle gophers. That narrow focus is on purpose. When you see the same patterns on hundreds of lawns, you start to read them: which ridges are dead ends, which runs are the highway, and where a mole will go when its tunnel gets wet.

So when a homeowner tells us they have been running a hose into the tunnels for a week, we are not surprised and we are not judging. It is the first thing nearly everyone tries. It just does not work, because a mole that gets flooded out does not die. It relocates, often a few feet away, and your lawn is wet and still damaged.

What we do instead is find the active runways, place traps where the animal will actually travel, and communicate clearly with you about what we found and what comes next. Moles are persistent, and new ones can move into good habitat, which is why we offer both a defined program for active damage and a year-round plan for properties that keep getting revisited.

— Mak

When to call a professional

Trapping is a skill that can be learned, and many homeowners manage it. But a professional makes sense when:

• You have already tried flooding, repellents or a few traps without results.
• The damage is spreading across a large lawn, a sports field, a garden you have invested in or a commercial property.
• You manage several properties and need predictable, repeatable results.
• You simply don’t want to spend your evenings probing tunnels.

Our 5-Week Mole Service is built for active mole damage: inspection, strategic trap placement and clear communication through the process, backed by a guarantee. If moles keep returning to your property year after year, The Mole Dominator Plan provides year-round protection. Property managers can look at our commercial mole control, and in Oregon we also offer gopher and vole control. You can see everything we do on our main site.

FAQ

Do moles drown when you flood their tunnels?

Usually not. Moles swim reasonably well, and their tunnel network is big enough that they can simply move to drier or deeper sections. Flooding can also draw worms upward, which may bring more mole activity to the area. Trapping in an active runway is the more dependable option.

Can moles swim across a pond or creek?

Most moles can cross a small creek, ditch or flooded area if they need to, helped by their small size and buoyant fur. They do not do it for fun, and they are not built for long swims. The star-nosed mole is the exception, since it forages underwater.

Can moles live in mulch?

They live in the soil beneath it rather than in the mulch itself. Deep organic mulch, compost and moist beds raise earthworm and insect numbers, which makes the soil more appealing. Swapping thick bark mulch for stone near foundations can reduce the attraction, but it will not remove a mole that is already there.

Do moles go away on their own after heavy rain?

Don’t count on it. Moles stay active all year, and wet weather often brings worms up and increases surface tunneling. If damage continues after a rainy spell, there is likely still an active mole in the yard.

What should I do if I find a mole in my pool?

Give it a way out with a rough board or net ramp and keep your bare hands off it, since frightened wild animals can bite. If it seems injured or exhausted, contact a licensed wildlife rehabilitator or your state wildlife agency. Then check your yard for the active tunnels it came from.

Sources

• Why do star-nosed moles have a ‘hand’ on their face? (Natural History Museum)
• Swimming ability of talpid moles, with particular reference to Condylura cristata
• Star-nosed Mole (SUNY ESF Adirondack Ecological Center)
• Living with wildlife: Moles (Washington Department of Fish & Wildlife)
• Moles (UC Statewide IPM Program)
• Controlling Nuisance Moles (MU Extension)
• Moles and Voles in the Garden, Oh My! (Tennessee Home and Farm)
• Expert: Get rid of moles now with know-how (Purdue)
• Mole Ecology and Damage Management (University of Wisconsin Extension)
• Goodbye Moles & Voles! (Clemson HGIC)
• Controlling the Eastern Mole (University of Arkansas Extension)