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Why am I seeing big roaches in my Pasadena home after it rains?
Most likely they are American cockroaches, the big reddish-brown “palmetto bugs,” and the rain pushed them in. Texas A&M AgriLife says American cockroaches are one of the most common cockroaches in sewer systems and live mostly outdoors, but may move indoors in search of food or water (Texas A&M AgriLife, Cockroach Biology and Management, 2017). The University of Florida adds that this roach is rarely found in houses, but infestations can occur after heavy rain, and that they migrate into homes from sewers through the plumbing (UF/IFAS Featured Creatures, American Cockroach, EDIS IN298, 2000). The fix is to find how they are getting in, close those routes and treat where they live outside.
Seeing roaches in your Pasadena home after the rain? Call or text Chris at 281-683-6737 for a free roach inspection. We answer evenings and weekends.
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When you call, tell us where you’re seeing them (bathroom, kitchen, laundry room, garage), how big they are, and whether you see them at night or during the day.
Why do Pasadena homes get roaches after storms?
A few things about Pasadena make it easy for outdoor roaches to end up inside after a heavy rain:
- Flat, wet ground between the bayous and the Ship Channel. Pasadena was founded in 1893 by John H. Burnett of Galveston, who named it after Pasadena, California, because of the site’s lush vegetation. He laid the town out on the southern bank of Buffalo Bayou, which became the Houston Ship Channel, and the Armand Bayou Nature Center is one of the city’s attractions today (Texas State Historical Association, Handbook of Texas, Pasadena). Bayous, trees and mulch beds are the kind of dark, moist places AgriLife says outdoor roaches live.
- Heavy rain is a regular event here. The Harris County Flood Control District says a major flood occurs somewhere in Harris County about every two years (HCFCD, Harris County’s Flooding History). When storm drains, sewers, mulch and water meter boxes fill with water, the roaches living there look for higher, drier ground.
- Many homes are 45-plus years old. Pasadena has about 149,400 residents and 53,800 homes. The median home was built in 1977, and about 37% of homes were built before 1970 (U.S. Census Bureau, American Community Survey 2020-2024 5-year estimates, tables B25035 and B25034, via Census Reporter). Older homes tend to have worn door sweeps, loose plumbing penetrations and drains in rooms that don’t get used much, which are the routes big roaches take.
- A big, connected city. Homes, apartments and businesses sit close together. AgriLife says once roaches are established, they can readily move within structures, such as from apartment to apartment.
Is it an American roach, a smokybrown roach or a German roach?
The size and where you see it tell you a lot.
| American cockroach (“palmetto bug”) | Smokybrown cockroach | German cockroach | |
|---|---|---|---|
| Size | 1 1/2 to 2 inches, the largest in Texas | 1 1/4 to 1 1/2 inches | 1/2 to 5/8 inch |
| Color | Reddish brown, tan to light yellow band behind the head | Dark brown to black | Light brown |
| Wings | Both males and females can fly | Long wings in both sexes, past the end of the body | Has wings but doesn’t fly |
| Lives | Mostly outdoors: sewers, drains, mulch, woodpiles, water meters | Outdoors: mulch, ground cover, palm fronds, soffits, attic eaves, tree holes | Indoors only in Texas: kitchens and bathrooms |
| After rain? | Yes, often comes up through drains | May move in from soaked mulch and trees | Not rain-related; it’s already breeding inside |
Sources: Texas A&M AgriLife, 2017; UF/IFAS, EDIS IN298.
That last row matters. A big roach in the bathroom the morning after a storm is usually an outdoor roach that found a way in. Small light-brown roaches in your kitchen cabinets are German cockroaches, and AgriLife says German cockroaches do not live outdoors in Texas, so those point to a problem already inside the house.
How do roaches get into a Pasadena house after a storm?
AgriLife says the larger roaches, like American and smokybrown cockroaches, often enter a home or business through poorly sealed doors, roof soffits or floor drains. UF/IFAS says American cockroaches also come in from trees and shrubs next to the house or with branches over the roof. The spots we check:
- Floor drains, tub drains and shower drains, especially in rooms nobody uses
- Gaps under exterior doors, patio doors and the door from the garage
- Holes where plumbing, A/C lines and cables go through the wall or slab
- Soffits and eaves, especially under trees
- Mulch, leaves and plants piled against the foundation
- Water meter boxes and cleanouts in the yard
Texas A&M’s school IPM program explains why the unused drains are the worst: when the water-holding trap in a drain dries out, cockroaches can come up from the sewer line more easily, and this happens most often with the large American cockroach (Texas A&M School IPM, The Science of Drainology, 2019).
Free roach inspection. Not sure if it’s a stray from the storm or a problem inside? Chris will check your drains, doors, plumbing, garage, soffits and the outside of your home, show you what he finds, and give you a price before any work starts. Book your free inspection or call or text 281-683-6737.
Is one roach after the rain a sign of an infestation?
Not always. One or two big roaches right after a heavy rain, near a drain or an exterior door, are usually outdoor roaches that wandered in. It’s a different story if you see:
- Roaches during the day. AgriLife says that usually means there are a lot of them.
- Small roaches in cabinets or around the fridge, stove and dishwasher, which points to German roaches.
- Droppings that look like crushed pepper in drawers and cabinet corners.
- Egg cases, small brown bean-shaped capsules, behind appliances and in cracks.
- Big roaches showing up week after week, even when it hasn’t rained.
How does CPL handle roach control in Pasadena?
CPL Pest Control LLC follows the integrated approach Texas A&M recommends: inspection, sanitation, sealing and targeted treatment.
- Free inspection. We figure out which roach you have, where it’s living, and how it’s getting in, inside and out.
- Outdoor treatment. For American and smokybrown roaches, we treat the places they live and the routes they use, like the foundation, doors, soffits, mulch beds and water meter boxes.
- Indoor treatment where needed. Baits and crack-and-crevice treatment where roaches hide, not just where you see them. For German roaches, see our German roach treatment page.
- Fixes and follow-up. We show you which drains, gaps and moisture spots to fix, and we come back as needed.
Here’s what one homeowner wrote in a Google review of CPL: “So you know how you would be walking to your kitchen. You turn on the light and you get surprised by one of these very, very large and obscene roaches. Your first thought would be I’m not dealing with this.” (Abraham Guerrero, 5 stars)
Pest control starting at $39.99/month. Initial pest control service of $179.99 is waived when you sign up now. Learn more about CPL Defense Basic.
Our guarantee: 30-day guarantee if you are not completely happy with our service. No contracts.
What can I do after a storm to keep roaches out?
These steps come from Texas A&M guidance:
- Keep drain traps full. Run water in tubs, showers, sinks and floor drains you don’t use much. Texas A&M’s school IPM program suggests flushing unused floor drains weekly with about a gallon of water, or screening them.
- Check the threshold seals under exterior doors, and make sure soffits are screened.
- Seal gaps around pipes and plumbing with a good-quality caulk or sealant.
- Pull mulch, leaves and woodpiles back from the foundation and doors.
- Fix leaks under sinks, at the water heater and at outdoor faucets, and keep mops and wet items off the floor.
- Empty pet bowls at night and keep trash closed.
- Put sticky card monitors near exterior doors, behind laundry appliances and in utility rooms. AgriLife says they’re most useful for finding where roaches are coming in.
For more on Houston-area roaches, read our roach control in Houston guide.
Frequently asked questions about roaches in Pasadena
Why do roaches come out of my drains after it rains?
American cockroaches are one of the most common roaches in sewer systems, according to Texas A&M AgriLife. UF/IFAS says they migrate into homes from sewers through the plumbing, and infestations can occur after heavy rain. A dry drain trap makes that easier.
Is a palmetto bug the same as a roach?
Yes. AgriLife says “waterbug” and “palmetto bug” are common names for the American cockroach.
Can American roaches fly?
Yes. AgriLife says both the adult male and female American cockroach can fly.
Will bug spray from the store fix it?
Usually not by itself. AgriLife says bug bombs generally don’t eliminate cockroaches because they don’t reach the cracks where most roaches hide, and that sealing entry points and keeping drain traps full matter for the outdoor species. A free inspection shows where yours are getting in.
Do you answer after hours?
We answer evenings and weekends at 281-683-6737.
Ready to get the roaches out of your Pasadena home?
Big roaches after a storm usually mean there’s an open path from the drains, the yard or the sewer into your home. Call, text or book online, and Chris will inspect your home and give you a price before any work starts.
Call 281-683-6737 | Text Chris | Book a free inspection
Related reading and services:
- Pest control in Houston, TX
- Roach control in Houston, TX
- The American roach in Houston, TX
- Tawny crazy ants in Pasadena, TX
- Contact CPL Pest Control
About the author: Christopher Villarreal owns CPL Pest Control LLC (Texas TPCL license 0567655) and has over 20 years of experience in pest control. CPL Pest Control LLC is licensed and insured and serves Pasadena and the Greater Houston area.
Published November 14, 2026.
