Moss Removal in Portland, Oregon: Broom, Hands, Then Plain Water

Which Portland rules come into play when moss comes off a roof or a sidewalk?

Moss removal in Portland, Oregon touches four city rules, one university source and one roofing trade group. None of them bans the work, but they decide where the moss goes, where the water goes and who trims the trees.

The owner and the sidewalk

Portland puts the sidewalk duty in City Code 17.28.020. That section, in short, puts the job on the owner of land beside a street. It covers the sidewalk, curb, driveway and parking strip next to that land. Liability follows too, if an unsafe stretch injures someone. Moss never appears in the text. Even so, the OSU Extension moss guide lists sidewalk moss as a slipping hazard and advises removal on busy paths.

Why the broom comes before the hose

The Environmental Services page on home wash water reads like a work order. Step one: sweep up visible solids and keep the sweepings. Step two: let water do only the final rinse, with no soap, chemicals, steam or heated water. If a job cannot meet that, the city sends the water to a planted or unpaved patch on the property. Our moss jobs follow the same order, which is why bags come out before hoses.

That page also cites City Code 17.32. Under it, water from any source needs approval before running onto public sidewalks or streets. When a slope allows it, the rinse heads into your own grass or beds.

When a street tree shades the roof

Portland street trees stand in the right-of-way, which the city describes as typically the strip between curb and sidewalk. Pruning any of them needs a city permit, according to the street tree pruning permit page. Still, one exemption covers branches below half an inch across where they join the stem. Every limb therefore stays as it is, because tree work is not ours. If one shades your roof, an arborist can seek the permit.

Shingles, valleys and the gutter line

• Joints and valleys: needles and moss jam where water slows, so this is where the hand work begins.
• North planes: ARMA notes they dry slowest, so they usually carry the thickest cushions.
• Pressure ceiling: rinse water on a roof never tops 500 PSI.
• Gutters below: anything that drops into them comes out on the same visit, if they are on your quote.
• Roof faults: if tabs lift or flashing works loose, the photo notes flag it for a roofer.

Underfoot and along the walls

• Sidewalks and driveways: thick moss comes up by hand, and then the rotating surface cleaner finishes bare concrete.
• Pavers and flagstone: a lower setting, since joint sand and softer stone wear away under force.
• Steps and decks: moss off by hand first, then a gentle setting suited to the wood.
• Block walls: damp caps and joints hold the moss, so pressure there stays light.
• Beds and drains: the crew soaks planting and then covers it, while storm inlets stay clear of moss.
• Photo pairs: you get both views of each quoted surface, before and after.

Siding is a different job, since algae streaks on walls call for a house wash. Our Portland house washing page handles walls.

Seven steps of moss removal in Portland, Oregon, from broom to photos

Here is what happens, in the same order on every lot. Step four matters most in Portland, because it keeps moss out of the storm drains.

1. Photograph each mossy surface.

   Use the form or call (971) 280-2861, then show the roof, the walks and any wall. We can often price a simple job from photos alone. However, a steep or large roof may need an in-person look first.

2. Accept the itemised written price.

   Every surface sits on its own line. After you accept, the total stays fixed on the work day, apart from work you add.

3. Soak the planting, then sheet it.

   Before anyone climbs, the crew waters nearby beds and lays sheets over them.

4. Broom and bag the loose growth.

   Loose moss and needles come up dry, so they never reach the curb or a storm inlet.

5. Pull the thick cushions out by hand.

   Joints, walk seams and wall caps then give up their moss to hands, working from the top down.

6. Rinse with plain water toward the lawn.

   Shingles take water at no more than 500 PSI. The spinning surface cleaner touches bare concrete only. All runoff then heads for grass or beds.

7. Empty booked gutters, then review the photo pairs.

   Next, if gutters are on your quote, the crew empties fallen moss from the troughs. Then you see each surface before and after.

Hands are slower than a jet. But the shingle granules stay put, and the drains stay clean.

Nine things noted before a moss removal price in Portland goes in writing

Below is what the free quote checks on a Portland moss job, using your photos or a description. If anything points to a repair, you hear it before you book.

• Material: asphalt, cedar, concrete, stone, wood or block, since pressure follows material.
• Moss depth: scattered tufts take little time, but a deep mat needs hands before any water.
• Roof pitch and stories: if planes are steep or there are two stories, expect $400 to $700.
• Area: because square footage drives it, walks and drive decide where the flatwork band lands.
• What casts the shade: because green returns first in shade, a street tree or north wall matters.
• Storm inlets nearby: when one sits close, the broom work grows and the rinse path changes.
• Beds by the house: anything planted under the eaves gets water and a sheet before work begins.
• Gutter load: when gutters sit full, the roof above sheds a lot.
• Water and parking: the hose needs an outside tap nearby, while the truck needs a place to stop.

Next reads for a Portland lot: roof, gutters, paving, walls

The roof has its own page, and so do the walls, the gutters and the paving. The statewide Oregon moss removal guide covers the biology.

Same city, next surface

Nearby moss pages, and booking

GreenTree Services, 1460 NW Van Buren Ave, Corvallis, OR 97330 · (971) 280-2861 · Oregon Registry #2424331-91

Sources: Portland Code 17.28.020. BES home wash water. Street tree pruning permits. Portland canopy update, 2026. NOAA airport monthly normals. NOAA airport annual normals. OSU Extension moss guide. OSU Extension roof moss. ARMA algae and moss. Oregon business registry search.