Call an exterminator when you see rats during daylight, find droppings in multiple rooms, discover gnaw damage to wiring or walls, or when two weeks of DIY trapping hasn’t stopped fresh signs of activity. Any one of these signals an established population that traps alone won’t solve. A single rat spotted once at night, or a small cluster of droppings in one location, can sometimes be handled with snap traps and sealing entry points. But rats reproduce fast enough that waiting too long can turn a manageable problem into a serious one.
Signs That Point to a Larger Problem
Rats are nocturnal, so you’ll almost always notice evidence before you see the animals themselves. Fresh droppings are the most common giveaway. They’re dark brown, shaped like large grains of rice, and tend to cluster in hidden spots: under sinks, behind appliances, inside cabinets, along garage walls. A single rat produces about 40 droppings per day, so a handful in one corner may just mean one animal. Droppings scattered across multiple areas of your home mean the population has spread.
Other signs of an active infestation include dark, greasy rub marks along baseboards and walls (rats follow the same routes repeatedly, leaving oil from their fur behind), rough gnaw marks on wood, plastic, or wiring, and scratching or scurrying sounds in walls or ceilings at night. A strong, stale, ammonia-like smell from urine is another indicator, and it gets noticeably worse as the population grows. Outside, look for burrows along your foundation. Active ones are 2 to 4 inches across with smooth, well-worn entrances and loose dirt fanned out around the opening.
You can test for ongoing activity by sprinkling flour or talcum powder in suspect areas and checking for fresh tracks the next morning.
The Clearest Trigger: Daytime Sightings
Seeing a rat during the day is the single strongest reason to call a professional. Because rats are nocturnal by nature, daytime activity typically means the colony has grown so large, or food is so scarce, that individual rats are being pushed out of hiding to forage. This isn’t a one-rat problem. By the time you see rats in daylight, you’re dealing with an established population that likely extends into wall voids, attic spaces, or deep burrow systems that snap traps can’t reach.
When DIY Efforts Aren’t Working
Snap traps are effective for catching individual rats, and they’re the recommended tool for small-scale problems inside a home. If you’ve set traps in the right locations (near droppings and along walls), baited them properly, and kept at it for about two weeks without seeing a drop in fresh droppings or activity, the infestation has outgrown what traps alone can handle. The remaining rats are likely nesting inside wall voids, attic insulation, or other spaces you can’t easily access or seal yourself.
Traps handle individual animals. They don’t address entry points, nesting sites, or the structural conditions that attracted rats in the first place. A genuine infestation requires a layered approach that includes sealing every gap larger than half an inch, removing food sources, and sustained monitoring over weeks.
Why Speed Matters
Rat populations grow alarmingly fast. A female Norway rat, the most common species in homes, can produce up to 12 litters per year with a gestation period of just 21 days. Litters can include up to 14 pups, though smaller litters are more typical. Even conservatively, a single breeding pair can produce dozens of offspring in a few months, and those offspring begin breeding themselves within weeks. What starts as two or three rats in your attic can become a full colony in a single season.
This reproductive speed is exactly why the “wait and see” approach backfires. Every week you delay gives the colony time to expand, establish new nesting sites, and cause more damage.
Health and Safety Risks Worth Taking Seriously
Rats carry diseases that spread through their urine, droppings, and saliva, often without direct contact. Dried droppings in poorly ventilated spaces like attics, crawl spaces, and basements can release airborne particles that transmit hantavirus when inhaled. Other diseases spread by rats include leptospirosis and salmonella, which range from mild flu-like symptoms to severe illness.
The property damage is equally concerning. Rats gnaw constantly to wear down their ever-growing teeth, and they chew through wood, plastic, pipes, and electrical wiring. Exposed wiring inside walls or attics can short-circuit and spark fires. Because rats travel through hidden areas, these fires can spread significantly before anyone notices. If you find gnaw marks on wiring, pipes, or structural materials, that alone justifies a professional call regardless of how many rats you think you have.
What Professional Extermination Involves
Professional rat control isn’t a single visit. Expect a sequence: inspection, pre-baiting, active trapping, structural sealing, and ongoing monitoring. During the first week, an exterminator typically places traps unset and pre-baited along rat runways so the animals lose their wariness of the new objects. Active trapping begins in weeks one and two, when the easiest catches happen. From weeks two through six, trapping continues alongside sealing entry points and eliminating food and shelter sources. Severe infestations involving attic colonies, wall-void nesting, or multiple outdoor burrows can take two to three months to fully resolve.
A couple of rats caught early may be cleared in a week or two. A typical infestation runs one to six weeks. The difference depends on how deeply the colony is embedded in your home’s structure.
When choosing a company, ask whether they use integrated pest management (IPM), which relies more on exclusion and trapping than poison. Poisoned rats can die inside walls and create a persistent, terrible smell. Any pest control company should be licensed and registered with your state’s department of agriculture.
What It Typically Costs
Most rat extermination services cost between $189 and $655, with an average around $395. An initial inspection runs $100 to $200, though many companies deduct that fee if you sign on for treatment. Exclusion work, which involves sealing all entry points, is usually included and ranges from $200 to $600. Follow-up visits cost $50 to $150 each and may be bundled into your initial estimate. Fumigation for severe infestations can run up to $1,500.
These costs are worth comparing against the price of repairing gnawed wiring, replacing contaminated insulation, or addressing water damage from chewed pipes. The longer an infestation runs, the more expensive the structural repairs become.
Quick Checklist: Call Now vs. Try DIY First
- Try DIY first: A single sighting at night, droppings in one location, no structural damage. Set snap traps along walls near droppings, seal visible gaps, and remove food sources. Monitor for two weeks.
- Call a professional: Daytime rat sightings, droppings in multiple rooms, gnaw damage to wiring or walls, burrows along your foundation, a strong urine smell, or continued activity after two weeks of trapping.
- Call immediately: Signs of electrical damage, piles of droppings, multiple nests, or dead rats in your home. These indicate a heavy infestation that poses real health and fire risks.