Which rodents will you actually meet in Washington, DC?
Two species account for nearly all residential calls in Washington, DC: the Norway rat and the house mouse. They behave differently enough that one treatment plan will not cover both. Norway rats are ground animals. They burrow in soil, under slabs, behind stoops and along foundation walls, and they forage outward from the burrow rather than living in your kitchen. UC IPM notes that a female produces four to six litters a year, weaning 20 or more offspring, which is why an unmanaged burrow beside a trash pad becomes a block-wide problem within a season. Across the District of Columbia, control means dealing with the burrow and the outdoor food source, not only setting traps inside. House mice are the opposite. They live entirely within the structure, nest in wall voids and cabinet backs, and can finish their whole lives without going outside. They need very little: crumbs, pet food and condensation. So the mouse fix is sealing plus interior trapping, while the rat fix reaches into the yard and the ground itself.
A month-by-month rodent calendar for Washington, DC
March through May is burrow season. As the ground softens with spring rain, Norway rats extend tunnels near foundations and trash storage. Walk the exterior then and mark every hole, because vegetation has not filled in yet. June through September is the quiet stretch that fools people. Summer highs near 89F and steady rainfall keep outdoor food and water abundant, so activity happens outside and you hear nothing indoors. This is exactly when exclusion work should be scheduled in Washington, DC, since crews can reach roof edges and crawl spaces easily and the animals are not yet in the walls. October through December is when the calls start across the District of Columbia. Overnight lows heading toward 28F push rats and mice against the building envelope, and the first scratching appears overhead. January and February are the hardest months to fix cheaply, because the population is nesting in insulation by then and the work involves cleanup as well as sealing.
What does the first inspection visit look like?
A useful first visit is mostly walking and writing, not spraying. Expect the inspector to start outside at ground level, checking the foundation line, stoop, utility penetrations, cellar door, dryer vent and any soil disturbance that suggests a burrow. Then they should get up to the roof edge, since gaps at soffits, flashing and vent stacks are the openings homeowners never see. Inside, they should be in the basement or crawl space tracing where plumbing and electrical pass through framing, and behind the stove and refrigerator looking for droppings and grease marks. In an attached building they should also ask what your neighbors are seeing. What you want at the end is a written list: each entry point, its location, and how it will be closed. If the report names only a trap count and a monthly fee, ask for the entry-point list before you sign. Ask too how many follow-up visits are included.
What actually moves the price on a rowhouse job?
The biggest driver in Washington, DC is spread. A mouse population confined to one kitchen is a short job. The same house with droppings in the cellar, the first-floor kitchen and a top-floor closet means the animals are using vertical chases, and the crew has to open, seal and monitor several levels. Second is the count and location of entry points. Ten gaps at grade that can be packed with steel wool cost far less time than three openings at a third-story roof edge needing a ladder, flashing and mortar work. Older District of Columbia masonry adds hours because sealing has to bond to something solid. Third is what comes after the animals are gone. Bagging out contaminated attic insulation and replacing it is a separate scope, and often the largest line on the quote. Follow-up visits and any exclusion warranty change the number too, so ask what the warranty covers and how long it runs. Get every quote in writing after an inspection, and compare the scopes rather than the totals.
Renters, landlords, and who has to fix the hole
Sealing a gap where a gas line enters a wall is a repair to the building. Keeping the kitchen clean is housekeeping. That line is what most rental disputes turn on, and it is worth knowing which side your problem sits on before the conversation starts. Document first. Photograph droppings with something in frame for scale, note dates and rooms, and photograph the openings if you can find them. Send the report in writing rather than by text, and keep a copy. If you live in an attached building, say so, because it tells the landlord the fix may reach past your unit. Meanwhile, do the parts that are yours. Move dry goods into hard containers, take trash out nightly rather than letting a bag sit, and stop leaving pet food down overnight. Removing the food supply genuinely slows breeding, and it takes the easiest objection off the table when you press for the structural work you actually need.