A line of ants across a kitchen counter is, in most Virginia houses, a housekeeping problem with a season. But one group of ants is a wood-destroying insect, appears on the form used in real estate transactions, and under the standard Northern Virginia contract obliges the seller to pay for treatment and for the repair of the damage it caused.
Telling the two apart takes about a minute, and the difference between them can be thousands of dollars at a settlement table.
This is general information. Species identification from a description is never certain. Keep a specimen and let a licensed inspector look at it.
The distinction that has money attached
The NPMA-33 wood-destroying insect report covers four groups: termites, carpenter ants, carpenter bees, and reinfesting wood-boring beetles.
Odorous house ants, pavement ants, acrobat ants, little black ants and the rest are not on it. They are a nuisance, they can be dealt with, and they have no bearing on a sale.
Carpenter ants are on it. That single fact changes what a sighting means when a property is under contract, and it is why an ant on a windowsill in March is worth thirty seconds of attention rather than a paper towel.
How to tell a carpenter ant from the others
Size, first. Carpenter ants are large — a quarter to half an inch, and the biggest ant most Virginia homeowners will see indoors. Nuisance ants are typically an eighth of an inch or smaller.
Colour. Usually black, sometimes black and red. Uniformly dark.
The back. Seen from the side, a carpenter ant's thorax is evenly rounded, a single smooth arch. Most other ants have an uneven, notched profile.
One node. A single bump on the waist between thorax and abdomen. Pavement ants and several others have two.
Coarse shavings, not a pile of dust. Carpenter ants excavate wood to nest in it rather than eating it, and push the debris out. What comes out includes recognisable insect parts and bits of soil. What left the sawdust →
Winged ones in spring can be mistaken for termite swarmers and are the reason that page exists. Ants have a pinched waist, bent antennae and forewings longer than hindwings; termites have none of those. Wings on the windowsill →
The inference that matters more than the identification
Carpenter ants excavate wood that is already damp or already damaged. Sound, dry framing is hard work; wood softened by a leak is not.
So finding them indoors is usually two findings at once: an ant problem, and a water problem that has been running long enough to soften structural wood. A gutter overflowing behind a fascia, a failed flashing, a shower pan leaking into a joist bay, a crawl space that never dries.
Treating the ants and leaving the moisture reliably produces their return. A company that quotes a treatment without asking where the water is has answered half the question.
The nuisance ants, briefly
Odorous house ants are the common small dark ant of Virginia kitchens. Crushed, they smell faintly of something like rotten coconut, which is the fastest identification available and the origin of the name.
Pavement ants come up through slab cracks and expansion joints, often in spring, often in enormous numbers for a few days.
Acrobat ants raise the abdomen over the body when disturbed, and — worth knowing — they too favour damp or previously damaged wood, so the moisture inference applies to them as well.
None of these are on the NPMA-33. What they mean is food, water and an entry point, in that order of usefulness.
What to do today
Do not spray the trail yet. A line of ants leads somewhere, and the direction is the most useful information you have. Follow it to where they enter and photograph that.
Collect two or three, in a sealed bag or between clear tape. Size and waist are what an inspector reads, and a photograph of a moving ant on a counter rarely shows either.
Look for moisture nearby. Under the sink, behind the dishwasher, at the base of an exterior wall, along the sill. If you find damp wood, you have probably found the real problem.
Then remove the food and water. Sealed containers, wiped surfaces, no standing water overnight. This does not solve a carpenter ant nest but it settles most nuisance species.
Do not fill any hole you find until someone has seen it.
What this means for you specifically
If you own and live in the home
For nuisance ants this is maintenance. For carpenter ants it is a moisture investigation that happens to have insects in it.
Your action: identify the species before treating, and if it is carpenter ants, find the water first. Ask any company you call what they think the moisture source is.
If you are selling under contract
Carpenter ant activity is a wood-destroying insect finding and belongs on the report.
The standard Northern Virginia contract requires the seller to furnish a wood-destroying insect report dated no more than 90 days before settlement, and to pay for treatment and for repair of the damage the report identifies, with written evidence before settlement. Damage from carpenter ants in a joist is repair, not just treatment.
Your action: deal with it before the inspection rather than against the settlement date, and expect the moisture repair to be part of it. The contract clause →
If you are buying
Ask specifically whether carpenter ant activity was found and whether it was described as current or previous.
Your action: read the section of the report listing what could not be inspected. Damp framing inside a finished basement wall is exactly the kind of thing that list covers. Reading the report →
If you rent
Ants in the occupied space touch your own duty under § 55.1-1227 to keep it free of pests. Ants in the structure, and the leak feeding them, are the landlord's through the habitability duty under § 55.1-1220.
Your action: report the moisture in writing, not just the ants. The leak is the part that is unambiguously theirs. Step by step →
If you are a landlord
A carpenter ant report is a structural signal. Treating repeatedly without finding the water reads badly if the tenancy later goes to a hearing.
Your action: have the moisture source identified in writing as part of the first visit. What you owe →
Before you call: what costs what
An inspection and a treatment are two separate services with separate prices, and with carpenter ants there is usually a third that nobody quotes at the start.
| Typical Virginia range | What it produces | |
|---|---|---|
| Wood-destroying insect inspection and report | $65–$200 | the NPMA-33 form |
| General pest inspection | often free where the company expects to quote treatment | a verbal or written assessment |
| Ant treatment | quoted per job; nuisance species are the cheaper end | a treatment record |
| Moisture and wood repair | quoted by a contractor | the reason it does not return |
What is usually free: a quote for treatment, once a company has seen the problem.
What is usually not: the inspection report used in a real estate transaction.
Ask which applies before you book, and for carpenter ants ask what the company thinks the moisture source is before you accept a treatment price.
Common misunderstandings
"Ants are ants." One of the four groups on the wood-destroying insect report is an ant. The rest are not.
"Carpenter ants eat wood." They excavate it to nest. Termites eat it. The galleries look different and so does the debris.
"Big black ants outdoors mean an infestation indoors." Carpenter ants nest outdoors routinely, in stumps and dead limbs. Indoors, in numbers, in winter, is the finding that matters.
"I sprayed and they're gone." A trail treatment kills foragers. The nest, and the wet wood it is in, are unaffected.
"It's just a spring thing." Pavement ants are seasonal. Carpenter ants active indoors in the middle of winter are nesting inside.
"They won't show on the report if I treat first." A report records damage as well as activity, and previous activity is a category on the form.
What to ask a pest control company
- Which species is this, and what supports that identification?
- Is this a wood-destroying insect for reporting purposes?
- Where do you think the moisture is, and does the price include finding it?
- Is the nest inside the structure or outside it, and what tells you so?
- What would a complete treatment involve, and how many visits?
- Under what name is your Virginia pesticide business licence held?
The third question separates a company solving the problem from one selling a visit.
What to have ready before you call
Where you see them and at what time of day, how large they are against something for scale, whether you have found any coarse shavings, any known leaks or damp spots, the age and foundation type of the house, and your settlement date if you are under contract.
Frequently asked questions
Are carpenter ants as serious as termites? Generally slower and more localised, but they are on the same report and carry the same contractual consequence in a sale.
Do carpenter ants sting? They can bite and may spray formic acid into the bite. It is unpleasant rather than dangerous for most people.
Why do I only see them at night? Carpenter ants forage largely after dark. Seeing a few by day often means a substantial colony.
Will removing the moisture fix it by itself? It removes the reason they chose that wood. An established nest still needs treating.
Does an ant sighting have to go on the NPMA-33? The report records what the inspector observes about the four covered groups. Carpenter ants are one of them; the small kitchen ants are not.
Verify before you pay anyone
VDACS publishes an updated list of licensed pesticide businesses weekly, with a public lookup confirming an active Pesticide Business License. General pest control is category 7a and wood-destroying pest control 7b under 2VAC5-685-70 — not category 8, which several sites state and which is public health pest control.
For carpenter ants, ask which category the company holds. If the finding is going on a report used in a sale, 7b is the one that matters. How to check →