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Mold Remediation in Portland, OR
Only about 3 percent of Portland's rain falls in July and August, so 42.9 inches arrive across a mid-October to mid-May wet season that keeps crawl spaces and wall cavities damp for months. One call reaches vetted local mold-remediation pros.
Recent floods · Portland
No recent flood events near Portland — see the live board.
Three of Portland's 12 federal disaster declarations were floods and four more were severe storms — water intrusions that seed mold long after the water drains. The area receives 42.9 inches of precipitation a year and only 2.8 inches of snow, so moisture arrives as prolonged cool-season rain rather than a brief melt, and wet framing, subfloors, and drywall dry slowly. The 2024 declaration for severe winter storms, straight-line winds, landslides, and mudslides is the most recent example.
Mold risk in Portland
42.9"
average annual precipitation (NOAA)
67%
of Multnomah County's 12 declared disasters were floods, hurricanes or storms (FEMA)
2024
most recent flood/storm declaration: Severe Winter Storms, Straight-Line Winds, Landslides, and Mudslides (FEMA)
Sources: FEMA OpenFEMA — federally-declared disaster history (county FIPS 41051) · NOAA NCEI — 1991–2020 Climate Normals (PORTLAND KGW TV, OR US)
What makes Portland a mold-prone city
Oregon health officials put the safe band for indoor humidity at 30 to 60 percent and treat moisture control as the whole of mold control. Portland's climate works against that band: 42.9 inches of precipitation a year against only 2.8 inches of snow means the water arrives liquid and repeated, across a cool season long enough that interiors rarely dry fully between storms.
Water events leave the residue. Flood and severe-storm declarations, aging combined sewer lines beneath older neighborhoods, and ordinary basement seepage all end the same way — wet framing, wet drywall, and a structure still damp after the visible water is gone. The building stock compounds it: city code can require an approved mechanical ventilation system for each bathroom that lacks one, a gap common in homes built before exhaust fans were standard equipment, and it treats visible growth beyond one square foot as a condition the owner must remediate.
The state issues no mold-specific contractor license — restoration work is licensed through Construction Contractors Board endorsements — and the statutory seller's disclosure form asks about flood and water damage rather than mold by name. For a homeowner in the area, that puts the burden on evidence: find the moisture source, and confirm a contractor's board standing before work begins. The mold remediation guide sets out the sequence.
Mold remediation rules & licensing
Mold work in Portland answers to a city housing-maintenance code rather than a state mold license. City Code 29.30.120 requires every dwelling, including basements, attics, and crawl spaces, to be kept reasonably free from dampness, with no moisture intrusion and no visible growth of mold or mildew; owners must remediate affected areas on discovery, and growth beyond one square foot can trigger a required bathroom ventilation system sized to state specialty code. The City Administrator administers and enforces the title under Chapter 29.60. The state licenses the contractor rather than the trade: the Construction Contractors Board Restoration Services endorsement carries bond and insurance minimums but no mold-specific training requirement.
| Permit / inspection | When it applies |
|---|---|
| City Code 29.30.120 — Interior Dampness | City level, and the only rule in the area that names mold directly. Every dwelling, including basements, attics, and crawl spaces, must be maintained reasonably free from dampness such that there are no sources of moisture intrusion from exterior or interior sources and no visible or otherwise demonstrable growth of mold or mildew inside the building. Property owners must remediate affected areas when growth is discovered. |
| City Code Chapter 29.60 — Administration and Enforcement | City level. Section 29.60.010 places administration and enforcement of the property-maintenance title with the City Administrator, who may inspect properties under 29.60.020 in coordination with Portland Permitting & Development and the Fire Bureau. Under 29.60.050 a violation notice goes to the owner by mail or posting and must state the violation, a compliance deadline, appeal rights, and a warning that penalties, charges, and liens may follow. Owners remain responsible for enforcement penalties until the condition is corrected and the City Administrator is notified. |
| Oregon Construction Contractors Board — Restoration Services Contractor endorsement | State level, binding on paid remediation work in the city. Oregon law requires anyone working for compensation on improvements to real property to hold a CCB license, so mold cleanup falls under it. The residential Restoration Services endorsement covers restoration for residential and small commercial properties only and carries a $15,000 bond and $100,000 liability insurance; a residential general contractor endorsement carries $25,000 and $500,000 and permits structural repair in the same job. No pre-license mold training is required for either. |
| Oregon Health Authority — Mold in the Home guidance | State level, guidance rather than a binding rule, and it explains what does not exist here. The health authority states that there are no standards to judge safe levels of indoor mold, meaning no clearance-testing threshold governs a completed job. It also states that county and state public health departments lack resources to inspect private homes or test for mold, so no agency signs off on residential remediation. The authority points to federal guidance recommending experienced professionals for mold problems larger than 10 square feet. |
Mold disclosure & remediation standards
- City Code 29.30.120 Administrative Rule (ENB-13.28) — Interior Dampness (Mold) violation protocols
- Local rule, effective October 28, 2020. It grades mold by aggregate area: a Minor Level finding of 10 square feet or less with an intact, cleanable substrate may be cleaned and painted by the owner or maintenance staff with no certification, while a Major Level finding above 10 square feet, or any smaller patch where the substrate is deteriorated, obliges the owner to hire a contractor holding an active third-party mold-remediation certification to identify the moisture cause, repair it, remove damaged substrate, and give the inspector a written summary of the work at final inspection.
- Title 29 Administrative Rule Section 3.3 — Bathroom Ventilation (per City Code 29.30.120 C & D)
- Local rule. Once visible or demonstrable mold exceeds one square foot in aggregate within a dwelling unit, every bathroom with bathing facilities must have a functioning mechanical fan vented through to the exterior of the building envelope and measuring at least 30 cubic feet per minute. Operable windows do not satisfy the requirement at that threshold, and an undersized existing fan must be repaired, fitted with a humidity-sensing or 30-minute timer switch, or replaced to Oregon Residential Specialty Code sizing.
- ORS 105.464 — Seller's property disclosure statement, Section 5.G
- State law. The statutory form a residential seller must deliver asks directly whether the dwelling has any moisture problems, areas of water penetration, mildew odors, or other moisture conditions, singling out the basement, and an affirmative answer requires the seller to explain the frequency and extent of the problem plus any insurance claims, repairs, or remediation performed. Section 9.C separately asks about material damage from floods, and Section 5.A asks whether the roof has leaked.
- ORS 90.320 — Landlord to maintain premises in habitable condition
- State law. The habitability standard never names mold, but it reaches the conditions behind it: subsection (1)(a) requires effective waterproofing and weather protection of roof and exterior walls including windows and doors, (1)(b) requires plumbing kept in good working order, (1)(i) requires ventilating and air conditioning facilities supplied by the landlord to be maintained in good repair, and (1)(f) requires the building be kept clean and sanitary. A rental unit failing these gives tenants statutory remedies.
Local mold notes
- Portland Healthy Homes Production Program (PHHPP) — In November 2025 the housing bureau moved to draw $2 million in HUD Healthy Homes Program funds for in-home health and safety work in 110 units, with roughly $950,000 of it paid as grants to property owners averaging about $8,000 per unit. Units where exterior or interior repairs for moisture or water damage are necessary are named as a remediation priority, alongside lead dust, elevated radon and electrical hazards.
- ENB-13.28 Section 3.1.4 — repeat mold complaints escalate to Major Level — A verified additional complaint of mold or mildew at the same address and unit within six months of a prior inspection or a closed case, where the earlier growth was cited as Minor Level, means any identifiable and visible growth confirmed on the later complaint is designated a Major Level violation.
- ENB-13.28 Section 3.1.3 — Occupant Protection Plan for occupied units — Before Major Level remediation begins in an occupied dwelling, the Certified Mold Remediation Contractor must prepare, or have a Certified Mold Inspector or Certified Industrial Hygienist prepare, a written Occupant Protection Plan unique to that unit, describing the planned work and the measures taken to protect occupants from spore exposure. A copy of that plan and of the contractor's certifications goes to the inspector before work starts.
- Multnomah County Healthy Homes Asthma Home Visiting Program — The county health department runs a free program for low-income families in which nurse educators and community health workers visit the home, covering medication management, an asthma action plan, and improving the health of the home — the environmental half of which addresses excess moisture and other asthma triggers. Eligibility is a child under 19 with asthma, county residency, and Oregon Health Plan income qualification.
Cleanup & recovery services nearby
- Metro Central Household Hazardous Waste Facility — Regional drop-off at 6161 NW 61st Ave. for paint, solvents, cleaning products, pool chemicals, batteries and double-bagged asbestos-containing materials pulled out during a cleanout — free for households with a 35-gallon daily limit, Monday through Saturday, 9 a.m. to 4 p.m.
- Portland Disposal & Recycling, Inc. — Family-operated hauler since 1936 renting roll-off drop boxes in 10-, 15-, 20-, 30- and 40-yard sizes — the container that soaked drywall, carpet pad and subfloor leave in.
- Recology Portland — Roll-off drop boxes in 10, 20, 30 and 40 cubic yards, open or closed, for residential and commercial customers inside the city limits — wood, concrete, furniture and demolition debris.
- Town & Country Glass Services — Glass shop on NE Halsey St. that boards up broken windows and doors after storm and weather damage, holding the opening until replacement glazing goes in.
- Urban Timber Tree Service Inc. — ISA-certified arborists on SE Harold St. (CCB #212995) removing limbs and uprooted trees off houses, cars and power lines after wind and saturated-soil failures, plus stump grinding.
- Broadway Storage PDX — Temperature- and humidity-controlled self-storage at 228 NE Broadway with keyless fob entry — somewhere dry to park furniture and boxed contents while drying equipment and repairs run.
By the numbers
- Average morning relative humidity — NOAA's 1948-2018 record puts the annual morning average at 82% against 59% in the afternoon.
- 82%
- Housing units citywide — Counted in December 2019: 154,422 single-family and 137,542 multifamily homes.
- 291,964