How Do You Know If Fleas Are Living in Your Carpet?

The White Sock Test

Put on long white socks pulled up over the trouser leg, and walk slowly around the room for a few minutes — deliberately over the areas where the pet rests and along the routes it walks. Then stop and look at the socks.

Fleas jump towards warmth, vibration and carbon dioxide, and against white they are easy to see. Anything small, dark and fast on the sock is your answer. Do it in the afternoon in a warm room, because a cold room in the morning gives a false negative.

The Damp Tissue Test for Flea Dirt

Comb the pet over a sheet of white paper, or brush the carpet pile firmly and collect what comes up. You are looking for small dark specks. Then put them on damp white tissue and wait a few seconds.

If a reddish-brown halo spreads out around the speck, it is flea dirt — digested blood — and that is conclusive. If it stays dark and does nothing, it is dirt. This is the test that separates "I think we have fleas" from a confirmed answer.

Where to Test

Not the middle of the room. Test where the animal lies: the pet bed and the carpet round it, the chair it uses, the sunny patch of hall carpet, and the foot of any bed it sleeps on. Then test along the skirting and the carpet edges, because larvae move away from light and end up deep in the pile at the edges of the room.

If there is no pet, test where the previous occupant’s pet would have been — usually near the back door, by a radiator, or in front of the sofa.

Reading How Bad It Is

Nothing on the socks after several minutes but flea dirt in the pile means a low or early population, or one that is mostly still in the egg and larval stages.

Several on the socks within a minute or two means an established population and there will be many times that number in the carpet as eggs, larvae and pupae. Bites around the ankles in a particular room is the same message — adults are emerging where you stand.

What to Do With the Answer

Confirmed fleas in the carpet is a property job, not just a pet job. Vacuum thoroughly and empty the cylinder outside, wash pet bedding hot, clear the floors so the whole carpet can be reached, and have the rooms treated — £180 for the first room and £60 for each one after.

Then keep vacuuming for a fortnight, even though it feels pointless. The vibration triggers pupae to hatch into a treated surface, and that is how the last of them are dealt with.