Mole Control in Washington State

What to look for

The animals are hunting earthworms and soil invertebrates, and they move quickly. WDFW measures tunneling at 15 feet an hour, with shallow runs advancing at quickly through soft soil. Population density varies enormously, from one adult per six acres up to more than five per acre. Washington's wet season west of the mountains keeps soil soft and worms high, which is why the damp side of the state carries most of the complaints while drier areas see far less. The Washington Department of Fish and Wildlife records three moles in the state: Townsend's mole, the Pacific or coast mole, and the shrew-mole. Townsend's is the largest mole in North America at eight to nine inches, and it is the one behind the biggest earthworks. WDFW describes molehills here running 6 to 24 inches across and 2 to 8 inches high, which is a substantial pile of soil to find in a lawn.

• 1Raised surface ridges (runways) that crisscross the lawn, often following the path of a mole's shallow feeding tunnel.
• 2Volcano-shaped mounds of loose soil, typically 2-8 inches tall, with a plug on top indicating a deep tunnel entrance.
• 3Soft, spongy turf that collapses when walked on, caused by tunnels just below the surface.
• 4Wilting or dying plants, especially in flower beds, due to roots being disturbed by tunnels.
• 5Mole activity near irrigation lines or garden borders where earthworms concentrate.
• 6Fresh mounds appearing overnight, especially after rain or watering.
• 7Multiple mounds in a line, indicating an active mole moving through a territory.

Treatment options and typical costs

Prices are typical published ranges. Ask what’s included before you compare quotes.

What Washington's trap law actually prohibits.

A company working in Washington should answer that immediately and without hedging. Second, when you hire someone, ask them to name their method and explain its legal footing. First, verify any device you buy is lawful in this state before it arrives. Two practical consequences follow. Moles themselves are unclassified in Washington, and property owners may trap or kill them on their own land when they are causing damage, so the restriction is about method rather than permission. What WDFW lists instead is non-body-gripping traps, flooding, shoveling, and habitat change. A product being sold online, or being legal in a neighboring state, tells you nothing about whether you may use it here. That matters because the harpoon, scissor-jaw, and choker-style traps recommended in extension publications from other states are exactly what most national mole advice points you toward. The Washington Department of Fish and Wildlife states that traditional body-gripping mole traps are illegal in Washington under Initiative 713, referencing RCW 77.15.192, RCW 77.15.194, and WAC 220-417-040, and it is explicit that there are no emergency exceptions. This is the part to get right before anything else.

Townsend's mole and the size of the mounds it leaves.

Grass under an eight inch pile of soil does not survive long, and the repair work grows quickly if you let a wet season accumulate. For practical purposes, level mounds promptly rather than leaving them. A larger animal working deeper main runs produces heavy mounding with relatively few of the shallow surface ridges people expect from mole photos, which is why some Washington lawns show piles of soil and almost no visible tunnel lines. Size also affects the damage pattern. The other two species, the Pacific or coast mole and the much smaller shrew-mole, work at a smaller scale, so mound size gives you a rough read on what is present. A pile at the upper end of that range is not a cosmetic blemish, it is a mower hazard and enough soil to smother the turf beneath it if left in place. The agency puts Washington molehills at 6 to 24 inches across and 2 to 8 inches high. WDFW identifies Townsend's mole as the largest mole in North America at eight to nine inches, and it lives here. Washington homeowners often describe mounds far larger than the ones in national photographs, and there is a reason for that.

Two Washingtons: the wet side and the dry side.

So advice that fits Seattle or Tacoma does not transfer neatly to Spokane, and a provider quoting on a dry-side property should be talking about irrigation as much as about the animal. The climate figures behind our 19 cities show why the western season runs so long: 73 percent median humidity, 38 inches of median rainfall, a 77F median summer high that rarely bakes the surface, and a 35F median winter low that rarely freezes it deep. Where damage does appear in drier areas, it is usually confined to irrigated ground, which forms a small island of suitable habitat. Drier ground supports far fewer earthworms, and the animal that must eat a large amount of them daily has little reason to be there. East of the mountains the picture changes. Damp soil holds earthworms near the surface, mild conditions keep the ground workable, and yards in the western part of the state can see mounds appearing for months on end. WDFW ties Washington mole activity to the wet season west of the mountains, and that description matches what homeowners report. The state contains coastal, temperate, continental, and arid zones in our data, and mole pressure differs sharply across them.

Planning around slow methods and a long season.

Ask a provider to estimate what they think they are dealing with before quoting a result. With WDFW's density range running from one adult per six acres to more than five per acre, a rural damp property may support several animals, and removing one changes less than it would in a state with sparse populations. Set expectations on numbers too. In a state with a long wet season this will not transform a property, but it reduces the strips of permanently saturated, worm-rich soil that hold an animal in one spot year after year. Fix chronically wet corners, redirect downspouts, and water established lawns deeply and less often. Then work on the habitat, which WDFW lists among the available methods. Those steps do not depend on removing an animal. Level mounds as they appear so turf is not smothered, roll collapsed runs so roots regain contact, and protect defined areas with buried hardware cloth around beds and specimen plantings. Start with what you can control outright. The realistic goal is often to reduce and manage damage steadily rather than to end it in a week. Because the fastest removal tools are unavailable here, Washington mole control asks for a different mindset.

Making sure the animal is a mole at all.

Arriving at that conversation with a clear description gets you a better answer and a more honest quote. Look at mound shape, check whether ridges rebuild after you flatten them, and inspect the base of any plant that is failing. Take ten minutes with a trowel before calling anyone. Pocket gopher mounds, where they occur, are fan or crescent shaped with a plug of soil at one edge rather than conical. Voles frequently use tunnels a mole dug, which is why the mole gets blamed. Narrow surface runways roughly two inches wide of clipped grass, stems cut cleanly at ground level, hollowed bulbs, and bark stripped from young trunks. Vole sign is feeding damage. The diet is earthworms and soil insects, at mostly earthworms by Penn State Extension's measure. Piles of finely broken soil pushed straight up with no opening visible, raised ridges that lift the sod, and turf that separates from the ground. Mole sign is mounded and structural, with no plants eaten. Two other animals get blamed for mole damage and need entirely different handling. Before spending money in a state where the options are limited, confirm what you have.

Simple ways to keep moles away

• Correct low areas that stay saturated through the wet season, since that is where worms concentrate.
• Pipe downspouts away from lawn instead of letting them soak one strip.
• Keep mulch thin so soil beneath beds does not stay wet all winter.
• Water established lawns deeply and infrequently rather than lightly and often.
• Bury hardware cloth about a foot deep around beds and plantings worth protecting.
• Walk the yard weekly during the wet season and note where new mounds appear.
• Level mounds promptly so the turf underneath is not smothered for weeks.
• Roll collapsed runs so grass roots regain soil contact.
• Check stems, bulbs, and young bark for chewing, which points to voles rather than moles.

Questions people ask

Related guides