Why are there so many rats in Baltimore alleys?
Alleys give Norway rats what they need in one narrow strip: cover along fences and walls, easy food from trash and spilled pet or bird feed, and burrow space in soft ground. Attached rowhouses also mean many back yards open onto the same alley, so one overfilled can or one broken fence can serve the whole block.
Rats follow edges. A fence line, a foundation or a retaining wall lets them travel without crossing open ground, and a rear alley is nothing but edges. Tall grass, stacked boards, covered trash and cluttered yards add hiding places.
The city knows this. In 2015, Baltimore's Department of Public Works reported that its Rat Rubout crew had grown to 16 technicians, up from eight, and planned to inspect and treat every alley on a 20-day cycle instead of the earlier 40 days. The city's stated reason was to interrupt the roughly three-week gestation of Norway rats. That plan covered 12,250 alleys. It is a 2015 report, so current staffing may differ, but it shows how much the alley is the front line.
Can I get rid of rats by myself?
Some rat problems can be reduced without a technician, mainly by securing trash, removing food and clearing hiding places. But rats already nesting in a wall, cellar or burrow usually need professional trapping and exclusion, because store-bought bait can be eaten by pets or wildlife and does little about the entry points.
Start with what you control. Use cans with tight lids, bring pet food inside at night, pick up fallen fruit, and keep wood and boxes off the ground. These steps reduce the food that keeps rats around, and the technician will often ask you to do them anyway.
What a homeowner struggles to do is read the signs. A technician knows the difference between an active burrow and an old one, can tell rat droppings from mouse droppings, and can find the small gap behind a cellar pipe that a flashlight scan misses.
- Use heavy trash cans with tight lids and keep them off the ground if possible
- Do not leave pet food, bird seed or compost uncovered at night
- Trim back dense ground cover and move wood piles away from the foundation
- Tell neighbours when you see rats, since the problem usually crosses the fence
How do rats get into a Baltimore rowhouse?
Rats enter through gaps around pipes and utility lines, cellar windows and vents, cracked or missing mortar, damaged door sweeps and broken sewer or drain connections. An adult rat can fit through an opening only slightly larger than a quarter, so even a small gap behind a radiator pipe or at a cellar door matters.
Brick houses are sturdy, but the points where utilities enter, where wood meets masonry, and where an old coal chute or vent was closed off are weak spots. In an attached house, rats can also run through shared wall voids and cellars from the house next door.
That is why sealing is done with durable materials that gnawing cannot defeat: metal mesh, steel wool combined with sealant, concrete patching and metal flashing. Foam or caulk alone is chewed through. If the building is part of a longer row, see how block-wide sealing works on the rowhouse pest proofing page.
What is the difference between a rat and a mouse problem?
Rats are larger, with droppings roughly the size of a raisin, and they dig burrows outdoors and gnaw heavily. Mice leave rice-sized droppings, live inside walls and cupboards, and travel only a few feet from their nest. The two need different traps, bait stations and sealing, so identification comes first.
A mouse can slip through a gap about the width of a pencil, while a rat needs a larger hole. A cellar with both pests is not unusual, since the same food and damp conditions suit them. The technician sets different devices for each and may stage the work so one does not scare off the other.
If you are not sure what you have, describe the droppings, any noises and where you saw the animal when you call. For indoor-only activity in cupboards and walls, our mouse control page may fit better.
