There is a straightforward test that answers this, costs nothing, and takes an afternoon plus two weeks of waiting.
Usually not. Most 'infestations' turn out to be several years of accumulated webbing plus a seasonal increase in visible activity.
The test: clear every web and egg sac, note the date, and look again in two weeks. What comes back — and how fast — tells you whether you have a real population.
This settles the question better than counting spiders.
| What you find after two weeks | What it means |
|---|---|
| A few new webs in the usual corners | Normal. No treatment needed. |
| Webbing substantially back throughout | Heavy population — treatment reasonable |
| Webbing back within days | Treatment warranted |
| Nothing much | It was accumulated webbing, not an active problem |
A large proportion of spider 'infestations' are several years of undisturbed webbing rather than a large current population. Clearing it is often the whole answer.
If this is late August to October, the answer is very likely yes.
Those big fast spiders crossing the carpet in the evening are mature males looking for a mate. They have been in or near your house all year without being noticed. It lasts a few weeks and ends on its own.
It is also the worst time to judge whether you have a persistent problem — and the most common time for people to book a treatment they did not need.
See our complete service, published room prices and honest advice on when treatment helps.
View Spider Control Harrow →If you genuinely have a lot of spiders, they will be concentrated in specific spaces rather than spread evenly:
Spiders spread evenly through a lived-in house is unusual and worth a conversation before booking.
None of these is a danger to a healthy adult. If you are unsure what you have, a photograph with your enquiry is genuinely useful.
No. Spiders come in from outside continuously. Treatment reduces the population for a period; sealing and clutter reduction is what makes it last.
We would not recommend a routine annual treatment. Do the physical measures and treat only when activity genuinely warrants it.
Spider numbers do vary year to year with weather and insect abundance. A busier autumn than last year is not necessarily an infestation.
Found something else? Wasp nest treatment across Harrow is £90 fixed cost with our guaranteed service.
Clear all the webbing and egg sacs, note the date, and look again in two weeks. Substantial return means a heavy population; a few new webs is normal.
Between late August and October, very likely. Mature males are moving about looking for a mate, and it ends on its own.
Garages, cellars, conservatories, porches and outbuildings — not evenly through a lived-in house.
No spider found in a British home is a danger to a healthy adult.
Dealing with outside lighting, sealing gaps, clearing webs and egg sacs weekly, and reducing clutter and perimeter habitat.
No. Treatment reduces the population for a period; physical measures are what make it last.
We would not recommend a routine annual treatment.
Do the two-week test first. If it comes straight back, that is a real population and worth treating.
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