Pest control in San Francisco follows damp wood and shared walls. Rodents move between attached houses through gaps at foundations, plumbing penetrations, and the voids beside bay windows. You hear them at night in a wall that is also your neighbor's wall. Ants show up in kitchens where a slow leak or a damp sill gives them a drink. Termites and other wood insects favor sills, porch steps, and framing that fog never quite dries. Pigeons and debris on flat roofs are a separate mess, but the entry points they exploit can be the same holes a rat will use later.
The structure is the map. A raised foundation with a tight crawl, a flat roof with a soft hatch, and a light well that stays dark are better clues than a product name. Trash storage, bird feeding, and ivy on a fence line feed the problem. Because houses touch, bait or a seal on only one side of a party wall may not stop animals that live in the gap. Droppings in an attic, grease along a pipe, wings on a sill, or softened trim should be identified before anyone treats the kitchen and leaves. Damp decay can look like insect damage. The finding has to be specific.
Fog keeps the pressure on. There is no hard freeze to knock populations back, and there is no dry attic heat like an inland city. Moisture is the attractant. Fix the drip under the sink, the gap at the sewer line, and the unscreened vent, or the trail returns after any treatment. Pets and small flats mean the method has to be careful in tight rooms. A roof deck with stored clutter is harborage. Say if you have seen activity in more than one unit of the building, without turning the call into gossip. The path is what matters.
Call with the sound or the dropping you found, and the level of the house. Mention a crawl space, a flat roof, or a shared wall. The work should close entries and address the pest that is actually using this damp, dense building.
Call the number on this page.