Rodent articles · Updated
Why rats come back after an exterminator, and how to stop it
Rats usually come back because a gap was missed or never sealed, the job relied on bait alone, food is still available, or rats keep arriving from a neighbor's yard. Finding and sealing the entry point is what ends it.
When rats come back after a job, it's almost always one of a few things: an entry point was missed or never sealed, the job relied on bait without sealing, food in the yard keeps drawing new rats, or the rats are coming from next door. Less often, a new gap opens, like storm damage on the roof.
The fix is to find out which one it is. Here's how to work through it.
The job was bait or traps only
Traps and bait clear the rats that are already inside. They don't stop the next ones. If the quote didn't include sealing, the gap is still open, and new rats find it by smell and habit. This is the most common reason for a quick return. Ask whether the original job included exclusion work, and what was sealed.
A gap was missed
San Antonio roofs have a lot of places for a roof rat to squeeze in: soffit corners, roof-to-wall joints, gable vents, plumbing vent boots and line set holes. On a two-story or a house with several additions, one missed seam is enough. Down low, a single open weep hole or a corner of the garage door can do the same for mice.
If you have photos or a list of what was sealed, compare it with where you're hearing noise now. The new activity often sits right next to a spot that wasn't on the list.
Want a local technician to take a look? Same-day appointments are often available.
Call (210) 955-2948
New damage opened a new gap
Hailstorms are common in San Antonio, and a new roof can leave fresh gaps at the drip edge and vents if the crew didn't close them. Summer heat shrinks and cracks door seals and sealants. A plumber, cable installer or HVAC tech can leave a new hole where a line goes through the wall. If rats came back after any of that, start there.
The food is still there
Pecans on the ground, citrus on the tree, open compost, bird seed and pet food keep rats coming to your yard even after the house is sealed. Rats that hang around a sealed house test it every night. Take away the food and they move on. Our prevention article covers it season by season.
The neighbors have them
Roof rats travel along fences, utility lines and connected tree limbs. If the house next door has rats in the attic, your sealed roof will still get visitors, and any small gap will be found. Trim limbs that connect your roof to theirs. If a neighboring property has junk piles or overgrowth, it can be reported through 311. See how to report rats in San Antonio.
Land clearing and construction nearby
On the growing edges of San Antonio, like the far West Side, the northeast suburbs and the corridors along Loop 1604, new phases of construction keep clearing brush. Each round scatters mice, Norway rats and woodrats into the nearest homes. If your problem came back right after the lot behind you was graded, that's a likely cause, and the fix is tighter sealing at ground level plus a few weeks of trapping.
A different rodent this time
Sometimes the rat that's back isn't the same kind. A house sealed against roof rats at the roofline can still let mice in through weep holes and a worn garage door. Check the droppings: smaller ones low in the house mean mice, and the low gaps need attention. Our droppings guide helps tell them apart.
Bait without sealing can backfire
When a job leans on bait alone, a few things tend to happen. Rats that eat bait may die inside walls or the attic and leave a smell. New rats move into the space the old ones left. And the gap that let them in stays open. If your last job was bait stations and nothing else, the next one should include an inspection of the roofline and the low gaps, followed by sealing.
What to ask for the second time around
Whether you call the same provider back or a new one, ask:
- Which entry points were sealed last time, and with what?
- Can you check the roofline and the low gaps again, including any new roof work?
- Will you trap inside before sealing the last opening?
- How many follow-up visits are included this time?
- What happens if they come back again?
Ready to have the gaps found and sealed? Call and describe what you're seeing.
Call (210) 955-2948
Questions from callers
How soon after a job is it normal to see rats?
A few stragglers in the first week or two while traps are working is normal. New activity a month later usually means an open gap.
Should I call the same company back?
If they offered a follow-up period, yes. Ask them to show you what was sealed. If they didn't seal anything, ask for a quote that includes exclusion.
Does a dead rat smell mean they're back?
Not necessarily. Rats that ate bait can die in walls days later. New droppings or noise are better signs of fresh activity. See dead rodent odor removal.
Can I prevent rats from coming back for good?
No house is permanent, but a sealed house with no food in the yard stays quiet for a long time. Recheck the roofline and low gaps once a year and after storms.