Stump grinding in Washington and Oregon

Grinding or removal: which one you need

A stump grinder is a carbide cutting wheel on a self-propelled machine, from walk-behind units that fit through a garden gate to tracked machines the size of a small excavator. It shaves the stump into chips in passes, working down below the surrounding grade, and it leaves the lateral roots in the ground to decay. The hole fills with a mix of wood chips and soil, and the lawn goes back over it within a season.

Stump removal means pulling the stump and its root plate out whole with an excavator or a stump puller, then backfilling the crater. It costs more, tears up more lawn, and is the right choice in three cases: a foundation, patio or driveway is going where the roots are; the tree died of laminated root rot and you want to replant a conifer; or a sprouting species has to be stopped at the root crown. The trade-offs by situation are on stump removal vs grinding. For do-it-yourself options, how to remove a tree stump compares five methods, stump remover chemicals explains what potassium nitrate and Epsom salt actually do, and how to remove tree roots covers the roots a grinder leaves behind.

If the tree is still standing, the stump is quoted separately from the removal. Portland’s code considers a tree completely removed once it is cut down to a stump no taller than 4.5 ft, which is why removal quotes stop there unless you ask [1]. See tree removal for the rest of the job.

How deep to ask for

There is no code depth for a private stump in either state, so put it in the quote. The common ask is grinding to 4 to 12 in below the surrounding grade: 4 to 6 in is enough to turf over, and 10 to 12 in gives room to set a new shrub or small tree nearby. If you plan to replant close to the old trunk, ask for the deeper end and for the surface roots within a couple of feet of the stump to be ground too, since those are what trip a shovel later.

The one published depth is Portland’s. For a street tree, the City Administrator can direct that the stump be ground out up to 18 in below grade [1]. That is a useful benchmark for any site where a replacement tree is required by permit, because a replacement planted into a shallow-ground stump has nowhere to put its roots.

Grinding wider costs more than grinding deeper: a flared western redcedar or bigleaf maple stump that measures 30 in across the trunk can be 50 in across at the ground, and the ground measurement is the one the grinder has to cut. Measure at the widest point at soil level, including the flare, before you ask for a price.

Call 811 before the grinder arrives

A grinder working 12 in down will cut a gas service line, an electrical conduit or a water line without slowing. Both states require a locate request before that kind of digging, and both put the duty on whoever is excavating, which is the contractor, not you.

Washington. RCW 19.122.030(2) requires notice to the one-number locator service, 811 or the Washington 811 website, not less than two full business days and not more than ten full business days before excavating; the marks are good for 45 calendar days after notice [2]. The statute exempts excavation less than 12 in deep on private noncommercial property by the owner or occupant (RCW 19.122.031), which covers hand-digging a flower bed and does not cover stump grinding to the depths above [3].

Oregon. The Oregon Utility Notification Center takes requests at 811 or 800-332-2344, with at least two full business days’ notice and not more than ten; the homeowner exemption is likewise limited to digging under 12 in deep on your own property outside easements [4]. The Center’s home page says a ticket is now valid for 30 days under a 2026 rule amendment while its FAQ still says 45; treat 30 as the safe number [4].

Why the grinder is not a rental-weekend job

A stump grinder’s wheel throws chips and stones hard and will pull in anything that touches it. OSHA’s tree care hazards page lists, among its caught-in cases, a California FACE fatality investigation (report 18CA002) in which a laborer died after being pulled into a stump grinder; it is out of region but the mechanism is the same on any machine [18][20]. Federal rules treat the machine accordingly: OSHA’s 2021 tree care inspection memo tells inspectors to check machine guarding whenever workers use brush chippers, stump cutters or chainsaws, and notes that the line-clearance standard requires stump cutters to be “equipped with enclosures or guards to protect employees” (29 CFR 1910.269(r)(4)(i)) [19].

What that means on your job: keep children, pets and yourself well back while the wheel is turning, move cars and anything with glass out of the throw line, and expect the operator to set up a guard or curtain on the side facing the house or the street.

What happens to the grindings

A 24-in stump ground to 10 in produces several wheelbarrows of chips mixed with soil, and the pile looks bigger than the stump did. Most crews rake the grindings back into the hole, mound it slightly, and leave the surplus for you; hauling is an add-on because the mix is heavy and not clean enough for a chip buyer.

Surface use is fine. WSU Extension’s review of wood chip mulch found that chips laid on the soil surface do not rob established plants of nitrogen, and that any deficiency is confined to the mulch and soil interface where it suppresses weed seed [5]. The same review says high-carbon mulches should not be mixed into planting soil and that wood mulch should never be used as backfill, which is the whole case against planting into a stump hole [5].

Three Northwest pest rules change the disposal answer. In Oregon’s Washington, Yamhill, Marion, Clackamas and Multnomah counties, ash stumps, roots, chips and mulch are regulated articles under Oregon’s emerald ash borer quarantine and cannot leave the quarantine area without an ODA compliance agreement; ODA allows movement only as chips one inch or smaller, kiln-dried lumber, or heat-treated wood [6]. For an Oregon white oak infested with Mediterranean oak borer, ODF says to chip the tree, stump included, to one inch or smaller on site, or burn it, and not to move oak firewood more than 10 miles [7]. In Portland, elm wood from a tree with Dutch elm disease must be disposed of within 24 hours and may not be kept as firewood (PCC 11.60.060) [8].

Replanting in the same spot

You can plant where the tree was, but not into the stump hole as the grinder left it. The chips tie up nitrogen as they decay, the mix settles for a year or more, and a sapling set into it sinks and starves. WSU’s advice on incorporated wood is unambiguous: never use it as backfill [5]. Dig the grindings out, use them as surface mulch somewhere else, and backfill with the native soil from the site or a topsoil blend.

Then plant to the ISA’s rule: a hole two to three times wider than the root ball and only as deep, with the trunk flare partially visible above the finished grade, and a 2 to 3 in mulch layer kept back from the trunk [9]. A tree set with its flare buried, which is easy to do in a soft stump hole, develops girdling roots and trunk rot years later. Offsetting the new tree a few feet from the old trunk center avoids the densest remaining roots and the softest fill.

Species choice matters when the old tree died of disease. ODF’s guidance for laminated root rot is to remove infected trees and susceptible hosts within a 50 to 75 ft buffer, then either remove the stumps or replant with resistant species; WSU adds that there is no chemical control and that hardwoods such as maple and alder are immune [10][11]. A grind-and-replant with another Douglas fir on that site repeats the loss.

Species notes: cottonwood, bigleaf maple, Douglas fir, ash

Black cottonwood is the stump that comes back. The US Forest Service’s species review says most regeneration in established stands is by root suckers or coppice sprouts, and that the species sprouts from stumps, root crowns and lateral roots after top-kill [12]. A ground cottonwood stump will sprout from the roots across the lawn; the fix is to grind the root crown out completely and mow or pull sprouts until the root reserves are spent.

Bigleaf maple is the Northwest champion at it. The Forest Service review reports that it sprouts from the root crown or stump after cutting, that sprouts can reach 10 ft in a year and 17 ft in three, and that one root crown can carry as many as 67 sprouts [13]. If you want a maple gone, the stump has to be ground below the root crown, not just to grade, and the first summer of sprouts has to be cut.

Douglas fir does not sprout, but its stump can carry laminated root rot. ODF says the fungus can survive for decades in large old stumps and roots and infects new hosts when their roots contact the old material, which is why its removal advice comes paired with stump removal or resistant replanting [10]. A fir stump on a site with no root rot is just a slow-decaying block of wood and is fine to grind.

Ash in the five Oregon quarantine counties is a disposal problem rather than a sprouting one: the stump and roots are regulated articles under OAR 603-052-1075 and stay on site or move under agreement [6]. Washington’s first emerald ash borer detection was confirmed near Vancouver in August 2026, and DNR’s guidance is to remove dead and dying ash and replant with non-host species [14].

What stump grinding costs

Grinding is priced by stump diameter because the wheel’s time scales with the area it has to chew. The site’s modeled rate, built on the same crew-cost basis as the removal model, is $4 to $6 per inch of diameter measured at ground level, with a $150 minimum for the trip and setup. Modeled estimate, not quotes (method).

What moves the number: a gate narrower than the machine, which forces a walk-behind grinder and more passes; surface roots to be ground; hauling the grindings; and grinding deeper than about 12 in for a replant. Several stumps on one visit spread the minimum across all of them. The stump grinding cost page works the examples, including when full removal is cheaper than grinding a cluster.

Public bid sheets price stumps the same way, by diameter band. The City of Tulsa, Oklahoma’s 2024 emergency debris contract (TAC 1326) asked nine bidders for a per-stump price in three bands, up to 24 in, 24 to 48 in, and over 48 in [21]. Those are Oklahoma municipal bulk prices, not Washington or Oregon prices, but one pattern carries over: for the same up-to-24-in stump, the nine bids ran from $114 to $600, so getting more than one written quote is worth the phone call.

When a permit touches the stump

None of the city tree codes checked for this site, 40 in each state, regulate grinding a stump on a private lot as a separate act. The permit question is whether the removal that left the stump was permitted, and whether that permit says anything about the stump.

Portland. The stump is handled inside the removal specifications rather than by a separate permit: a tree is completely removed at a stump no taller than 4.5 ft, the owner decides how to dispose of a private tree’s wood as long as storing it creates no public health or safety nuisance, and for street trees the City can require grinding up to 18 in below grade [1]. Where the permit carries a replacement condition, the stump has to be dealt with well enough to plant the replacement, and the 18-in street-tree figure is the practical benchmark.

Seattle. SDCI’s tree removal page does not mention stumps or stump grinding, so a stump left after a permitted removal is not itself regulated there; if the tree was in the planting strip, the SDOT street-tree permit governs the strip, and the thing to confirm with SDOT is whether the stump must be ground before the replacement goes in [15]. Everywhere else, the city rows in tree removal permits in Oregon and tree removal permits in Washington tell you whether the removal itself needed a permit; if it did, keep the permit number with the grinding receipt.

Both states’ timber trespass statutes apply to stumps too. Grinding out a boundary tree’s stump on the neighbor’s side of the line can be treated as injury to their tree under ORS 105.810 and RCW 64.12.030, with treble damages, so settle the line before the grinder arrives [16][17].

Stump grinding by area

Statewide rules, costs and storm seasons: Stump grinding in Washington · Stump grinding in Oregon.

• Stump grinding in Bend
• Stump grinding in Eugene
• Stump grinding in Gresham
• Stump grinding in Hillsboro
• Stump grinding in Portland
• Stump grinding in Salem
• Stump grinding in Bellevue
• Stump grinding in Seattle
• Stump grinding in Spokane
• Stump grinding in Tacoma
• Stump grinding in Vancouver

Related guides

• How to remove a tree stump: 5 ways compared for WA and OR yards
• Stump remover chemicals: what potassium nitrate and Epsom salt really do
• How to remove tree roots after the tree is gone, and when to leave them
• Stump grinder rental: WA and OR rates and the rent-or-hire math
• How to kill a tree stump: stop sprouts, speed rot or grind
• Free wood chips: getting arborist mulch in WA and OR