Rats in Seattle: Norway Rats, Roof Rats and What to Do About Them

Which rats live in the Seattle area?

The Norway rat and the roof rat are the two common species in Washington. Norway rats, also called brown rats, are stocky burrowers that live low, under decks and along foundations. Roof rats are slender and darker, climb well and are found on roofs, in trees and in upper levels of buildings.

Which one you have changes the plan. Burrow holes along a fence and droppings in a basement suggest Norway rats; running sounds overhead and rub marks along a roofline suggest roof rats. They can occur on the same property, and a technician confirms the species from the evidence.

Neither is a sign of a dirty home. Rats follow food, water and cover, and a neighbor's overflowing bin can be enough.

How do rats get into a Seattle house?

Through gaps most owners never notice: torn crawl space vent screens, openings around pipes and cables where they pass through the foundation, worn garage door seals, gaps behind downspouts and rotted fascia or soffit boards. Rats need far less room than people expect, so small openings count. Finding all of them is the core of the job.

Many older and hillside Seattle homes have crawl spaces or daylight basements, and the foundation, vents and utility penetrations there are the usual entry. Roof rats add rooflines, vents and tree limbs that touch the building.

Walk the outside with a flashlight, looking up as well as down. Note torn screens, daylight around pipes, gnawed wood and branches that bridge to the roof. A technician checks the same places, and a list of what was found helps you plan the sealing.

• Foundation and crawl space vents with torn or missing screens
• Gaps around pipes, cables and gas lines
• Garage door seals and door sweeps
• Fascia, soffits and roof vents
• Branches, vines or wires that reach the roof

Why remove food and shelter before using poison?

Because rats return to whatever feeds and shelters them. Public health guidance puts removing food and shelter first, and says poisons are not recommended inside buildings and are risky for children, pets and wildlife. A rat that eats bait can also die inside a wall, leaving a smell and a repair job.

Food means more than the kitchen. Open bins, pet food left out, birdseed, fallen fruit and compost all count. Shelter means woodpiles, brush, dense ivy, clutter against fences and gaps under sheds.

A visit that starts by identifying the animal, tracing the route in, and removing the attractant addresses the cause. Baiting without those steps usually delays the problem. See rat control for how a visit runs.

There is also a practical reason to be patient with this order of work. Rats learn. A rat that survives a poorly placed trap or avoids bait becomes shy of the device, which makes later control harder. Removing food and cover makes every other step work better, and sealing finishes the job.

• Tight-lidded bins, emptied before they overflow
• Pet food and birdseed stored indoors at night
• Fallen fruit and compost managed
• Woodpiles and brush lifted and moved away from walls
• Gaps sealed with metal, not foam

How do I file a rodent complaint in King County?

Public Health - Seattle & King County takes rodent complaints at no fee through its rodent complaint page. In some cases it can enforce King County Board of Health Title 8 rodent rules, and it baits sewers in Seattle. The county route is most useful for neighboring garbage, vacant lots and problems that span properties.

The complaint is free and can be filed online. You will be asked where the rats are, what you have seen and whether it is on public or private property. It does not remove rats from your own walls, which remain the owner's job.

Use both routes when they apply. File a complaint about the neighbor's overflowing bins, and call a technician to find and close the entry points in your own building.

Are rats worse in certain months or neighborhoods?

No current Seattle figures are available. A 2004 regional newspaper report said King County's third-quarter rodent complaints ran about 30 to nearly 70 percent above other times, so late summer has historically been busier. Many people also notice rodents seeking shelter as the rains return, but treat that as experience, not data.

Rats are active all year, and a new sign in any month is worth checking. Late summer into fall can bring more complaints when populations are large and the weather turns, but the evidence is old and local conditions vary.

Do not wait for a season to act. A gap is easier to close before a litter is born, and a single rat is simpler than a family.

There is no current ranking of neighborhoods. Local news stories over the years have described sightings around busy restaurant and alley districts, but those are anecdotes and not counts. Rats follow food and cover, so any block with open bins, old buildings or a nearby greenbelt can have them.

Wooded ravines and greenbelts on the Eastside and north end shelter roof rats, which climb from trees to eaves. Whatever your neighborhood, check your own property for the three basics: food, cover and an opening.

What are the health risks, and how do I clean up safely?

Hantavirus is a stated risk from rodent droppings and urine, and rats can contaminate food and surfaces. Avoid stirring up dust. Do not sweep or vacuum dry droppings; wet them with disinfectant, wipe up with a paper towel, wear gloves and bag the waste. Tell a doctor about any exposure if you develop fever or breathing symptoms.

Most households that find rats do not become ill, but the precautions are cheap. Ventilate an enclosed space for a while before cleaning, and consider a mask for an attic or crawl space with heavy contamination.

For a large cleanup, ask a technician or a cleanup specialist. Soiled insulation often needs removing.

Wear gloves, air out the space, wet droppings and nesting material with disinfectant, wipe up with paper towels and bag everything. Do not sweep or vacuum dry material, because dust can carry the virus the guidance warns about. Heavily soiled insulation in an attic or crawl space usually needs professional removal.

If anyone in the household gets a fever, chills or breathing symptoms in the weeks after cleaning up rodent droppings, tell a doctor about the exposure.

What about rats in apartments, restaurants and shared buildings?

Shared walls, shared bins and shared basements mean one unit's problem can be the building's problem. Tell the landlord or manager in writing, report overflowing dumpsters to the county, and ask for a building-wide inspection. Businesses with food on site are best served by a scheduled program with monitoring and records.

In a multi-unit building, the entry may be far from the unit where rats are heard. A gap in a basement wall or a broken door at a trash room can serve every floor. Coordination matters more than any single treatment.

For businesses, see commercial pest control. For tenants, Washington law gives landlords a duty to reasonably control pest infestations not caused by the tenant, outside single-family homes; this is information, not legal advice.

Report the problem to management even if you have only heard noises. Tenants who give notice early leave a record, and rats in a building are rarely limited to one unit. If shared bins or a blocked drain are the draw, say so in the same message.

What can I do now, and when should I call?

Today: secure food and bins, bring in pet food and birdseed, clear brush and woodpiles from walls, note where you see signs and keep children and pets out of the area. Call when you hear activity in a wall or attic, find droppings indoors or see burrows. A technician identifies the species and closes the entries.

Resist the urge to set poison. If you want to act before the visit, place a few snap traps along walls where pets and children cannot reach, and tell the technician what you did.

A technician identifies the species from droppings, damage and runways, traces the route in, finds the food and shelter drawing the rats, agrees the price with you, then uses traps, or bait in secured stations where suitable. Entry points are sealed and a return visit checks that activity has stopped.

A same-day visit is offered only when a technician is free, and the price is confirmed before any work. For sealing, see rodent exclusion and crawl space sealing, and for mice mouse control.