Why are bed bugs still there after treatment?

Bed bugs after a treatment usually mean the treatment is not finished, not that it failed. The EPA says very few infestations are controlled with only one treatment,^[1] and bugs seen in the first days or weeks can be survivors, newly hatched eggs, or hitchhikers from next door. What matters is whether the numbers fall at each check and whether the company is coming back.

The usual reasons bugs show up again

Eggs hatch after the visit. At room temperature, bed bug eggs hatch in about a week.^[4] Most treatments kill the bugs they reach, and a second visit exists to catch what hatches afterward. The EPA puts the logic this way: if you see bed bugs, either the initial cleanup missed some bugs or eggs have hatched, and retreatment may be needed.^[2]

Hiding places were missed. Bed bugs sit in cracks and crevices, so a surface spray alone has limits; the EPA says a fogger's spray will not reach the cracks and crevices where bed bugs hide.^[2] That is also why a technician may take furniture apart and inspect outlets, baseboards and bed frames.

The bugs resist the product. Bed bugs are becoming increasingly resistant to pesticides.^[4] The EPA goes further: bed bug populations in different areas of the country have developed resistance to the ways many pesticides work to kill pests, and if you're dealing with a resistant population, some products and application methods may not work.^[3] Proper use of pesticides may be part of the strategy, but will not by itself eliminate bed bugs.^[3] If repeated treatments are needed, the EPA suggests considering different types of pesticides.^[2]

Heat killed what it reached, but nothing is left behind. Heat alone has no lasting (residual) effect should bed bugs be reintroduced into the dwelling,^[4] and Virginia Cooperative Extension writes that because we cannot expect even the best heat treatment to always be 100% successful, it makes sense to ask the technician about a residual product afterward.^[5] See how heat treatment for bed bugs works.

New bugs came in. Neighbors, a shared wall, or items brought home can restart an infestation. The EPA lists whether your neighbors have bed bugs, and whether all residents of a house or building participate, among the factors that decide success.^[2]

Preparation was incomplete. Items left unbagged, clean laundry stored next to untreated areas, or rooms the company could not access all leave refuges. The details are in how to prepare your home for bed bug treatment.

What to do now

Do not panic and do not start spraying. Treating bed bugs is complex and can take weeks to months, depending on the extent of the infestation.^[2] Anyone you hire should use IPM, which will include monitoring for any bugs that have been missed during treatment.^[1] Your job in between visits is to monitor and report.

Look for evidence every few days.^[2] Interceptor dishes under the legs of the bed and seating catch wandering bugs; check and clean them every week,^[2] and continue to inspect at least every 7 days in case any eggs remain.^[2] Write down what you find and where, with dates. A log showing three live bugs in week one and none by week four tells a different story from one that stays flat.

Then call the company. Ask when the follow-up visit is scheduled. Virginia Cooperative Extension's guidance on heat treatments says your pest management company needs to provide a follow-up inspection within a week.^[5] Ask what will change if bugs are still there: a different product, a dust in hard-to-treat spots, heat, or a second pair of eyes with a flashlight. If you rent, tell your landlord, because the EPA says to notify your landlord if you live in an apartment and that the units near yours should be inspected.^[2]

What not to do

Do not try to finish the job with the thermostat. The EPA says do not try to kill bed bugs by increasing your indoor temperature with a thermostat, propane space heater, or fireplace - this does not work and is dangerous.^[2] Bleach, alcohol, cigarette lighters and "bug bombs" (foggers) should not be used either, because they are ineffective and can result in fires and other dangerous outcomes.^[4] Do not throw out the mattress in a hurry; moving infested furniture can carry bugs through the home, and the company can tell you whether it needs to go.

Stop and call a pro if

• You still see live bugs after the follow-up visit. Ask the company in writing what it will do differently, and how many visits the price covers.
• Bites or bugs spread to new rooms. That is worth reporting to the company straight away, because it suggests the treatment has not reached every hiding place.
• The company has not returned for a follow-up. Very few infestations are controlled with only one treatment.^[1] Ask the company when it will return.
• A neighbor's unit is the likely source. In a rented home, report it to the landlord; the EPA says the units near yours should be inspected.^[2]
• You are tempted to use foggers or a heater. Both are dangerous and ineffective, as above.

Getting help in Virginia

For what a second round costs and who pays in a rental, see how much bed bug treatment costs in Virginia and whether a landlord is responsible for bed bugs in Virginia. Loclis lists licensed pest control businesses: browse pest control or read more pest control answers.

When you are ready, describe the job on Loclis so licensed pest control businesses can quote it in writing.