After the storm: a dump-and-drain mosquito checklist for DFW yards

After a storm, walk your yard once a week and empty, scrub, turn over, cover or throw out anything that holds water, because mosquitoes lay eggs in standing water and can go from egg to biter in a matter of days. Pair that container sweep with an EPA-registered repellent and screens in good repair, especially during the West Nile season.

Why do mosquitoes boom after rain in North Texas?

Rain fills every low spot, bucket and saucer in the yard, and mosquitoes are quick to use it. Texas A&M AgriLife entomologists describe mosquitoes arriving in waves after heavy rains: floodwater species first, then container mosquitoes, then Culex mosquitoes as the water recedes and stagnates. According to the same AgriLife report, it takes "a matter of days" for these mosquitoes to go from egg to biter.

That timeline is why the advice is weekly, not monthly. A birdbath you forget for two weeks after a spring storm can raise a new batch before you notice.

Know the suspects

You do not need to identify every mosquito in the yard, but it helps to know which habits you are fighting. Texas A&M AgriLife describes three groups that show up after rain:

• Floodwater mosquitoes. Larger, aggressive biters that follow heavy rain in ditches, fields and low spots in lawns.
• Container mosquitoes (Aedes). Small, black mosquitoes with white stripes on the back and legs. Females lay eggs in anything holding water, from tires and buckets to gutters and trash cans, and they prefer cleaner, fresher water. They are daytime feeders.
• Culex mosquitoes. These prefer stagnant water with high bacteria content, such as a neglected pool. AgriLife identifies Culex as the group that transmits West Nile virus.

For a closer look at mosquito biology and habits, see the mosquito profile. The illustrations on this site are drawings, not identification photographs.

What is West Nile virus, and when is the risk highest?

The CDC calls West Nile virus the leading cause of mosquito-borne disease in the contiguous United States. It spreads mainly through the bite of an infected mosquito, and cases usually begin in summer and continue through fall.

Most people who are infected never feel sick. The Texas Department of State Health Services notes that about 80% of infected people have no symptoms. According to the CDC, about 1 in 5 develop a fever with symptoms such as headache and body aches, and about 1 in 150 develop severe illness affecting the central nervous system. There is no vaccine or specific antiviral medicine for people, so the CDC's guidance is that preventing bites is the way to prevent infection.

Locally, the season is long (see the DFW pest calendar for how it fits the rest of the year). When Tarrant County Public Health confirmed its first West Nile-positive mosquito samples of 2026 in May, it noted that activity typically increases from May through October as warmer weather drives up mosquito activity.

The dump-and-drain checklist

Do this sweep once a week from spring through fall, and again within a few days of any heavy rain. The CDC's home mosquito control guidance is simple: once a week, empty and scrub, turn over, cover or throw out items that hold water.

Around the yard

1. Buckets, wheelbarrows and watering cans. Empty them and store them upside down or under cover.
2. Flowerpot saucers and planters. Pour out the water and scrub the saucer so eggs stuck to the sides do not hatch next time it fills.
3. Birdbaths. Dump and refill weekly, and scrub the bowl.
4. Pet water dishes. Change the water often and scrub the bowl.
5. Kids' toys and wading pools. Tip them out and store them where they cannot collect rain.
6. Old tires. Get rid of them, drill drainage holes, or keep them under a roof.
7. Pool covers. Drain water that pools on top after rain; the CDC lists pool covers among the places mosquitoes lay eggs.
8. Trash and recycling bins. Keep lids closed and drain any water caught in the bottom or lid.

Around the house

9. Rain gutters and downspouts. Clear leaves so water flows instead of pooling. AgriLife lists gutters among the places container mosquitoes lay eggs.
10. Leaky outdoor faucets. Fix drips that keep a container or low spot wet.
11. Rain barrels and water storage. Cover them tightly. For containers without lids, the CDC suggests wire mesh with holes smaller than an adult mosquito.
12. Pools. Keep them maintained. AgriLife notes that unkept pools can support container mosquitoes, and stagnant water suits Culex.
13. Septic tanks and open pipes. The CDC advises repairing cracks or gaps in septic tanks and covering open vent or plumbing pipes with mesh.

Inside

14. Indoor containers. The CDC recommends the same weekly sweep indoors: vases, plant trays and anything else that holds water.
15. Screens and doors. Install or repair window and door screens, keep doors closed, and use air conditioning when you can.

What about water you can't dump?

Some water cannot be emptied or covered, like an ornamental pond, a rain barrel you rely on, or a low spot that stays wet. For that water, the CDC describes larvicides, products that kill mosquito larvae and pupae before they become biting adults. The CDC says they are for water that will not be used for drinking and cannot be covered, dumped or removed.

Larvicide ingredients you may encounter, as named by the CDC, include the bacterium Bti (Bacillus thuringiensis subspecies israelensis), spinosad, Lysinibacillus sphaericus, and the insect growth regulators methoprene and pyriproxyfen. This is educational context, not a recommendation of any product.

The label is the law. The EPA's pesticide label guidance points to the federal statement printed on labels: it is a violation of federal law to use a product in a manner inconsistent with its labeling. For a walkthrough of what a label tells you, see how to read a pesticide label. The CDC adds a practical rule: do not apply more than directed or reapply more often than the label instructs. For questions about a specific product, the National Pesticide Information Center can be reached at 1-800-858-7378.

Which mosquito repellents work?

The CDC recommends using an EPA-registered insect repellent with one of these active ingredients:

• DEET
• Picaridin (known as KBR 3023 or icaridin outside the U.S.)
• IR3535
• Oil of lemon eucalyptus (OLE)
• Para-menthane-diol (PMD)
• 2-undecanone

Look for an EPA registration number on the label. The EPA's repellent search tool explains that this number means the company gave the EPA information on the product's safety and effectiveness. You can use the tool to compare registered products by active ingredient and how long protection lasts.

Use repellent safely

The CDC's guidance includes these points:

• Follow the product label every time.
• If you use sunscreen, apply sunscreen first and repellent second.
• Do not apply repellent to skin under clothing.
• Do not use products containing OLE or PMD on children under 3 years old.
• For babies, dress them in clothing that covers arms and legs and cover strollers and carriers with mosquito netting.
• Permethrin is for treating clothing and gear only. Do not use permethrin products directly on skin.

The CDC also notes that EPA-registered repellents are safe and effective for people who are pregnant or breastfeeding when used as directed.

How do you ride out mosquito season?

Containers and repellent do the heavy lifting, but a few habits help close the gaps:

• Cover up. Tarrant County Public Health recommends loose-fitting long sleeves and pants outdoors, especially at dawn and dusk.
• Watch the clock. The same county guidance suggests staying indoors during peak mosquito hours when you can. Remember that container mosquitoes bite during the day, so a midday yard sweep still calls for repellent.
• Keep the house sealed. Screens without holes and closed doors keep biters outside.
• Follow local alerts. Tarrant County Public Health, for example, tests mosquito samples during the season and announces positive results. Check your own city or county health department for local updates.

When to get help

If water problems are bigger than a weekly sweep, such as a drainage ditch, a neglected pool next door or standing water on public property, contact your city or county code or vector control office. For a persistent mosquito problem on your own property, a licensed pest professional can assess breeding sites; in Texas, the Structural Pest Control Service of the Texas Department of Agriculture licenses applicators who treat in and around structures.

If you or a family member develops a high fever, severe headache, stiff neck, confusion or muscle weakness during mosquito season, seek medical care promptly. For questions about a repellent or pesticide exposure, call Poison Control at 1-800-222-1222.

This field guide is educational and does not offer treatment bookings.