Only it isn't. There are far germier parts that we would not even think twice about as being health risks.
A study has found that the average toilet seat has about 50 bacteria per 6.45sq cm, or the old-fashioned square inch. From now on, we will use that as a measure. The LSGL or loo seat germ level.
So with this in mind, let's go about our day and check out the levels of greeblies we come into contact with.
Hands are one of the dirtiest parts of the body, so every time we open a door we are mixing with other people's grubbiness.
Light switches have up to four times a loo seat of germs, or 4 LSGL.
Your desk at work is likely to be 400 LSGL and the keyboard not much better at 200 LSGL.
If you think that's gross, how about your mobile phone? It rates 10 LSGL - 10 times grubbier than a toilet seat. Or handling money, which is a skin-crawling 4000 LSGL.
I shouldn't mention this one, but for your safety I will. Did you know menus have 100 times more bugs on them than the restaurant's loo seat?
Ewwwwww.
Mind you, if we thought about all this stuff all the time we would go nuts.
Would you mind opening the curtains at home if you knew just how efficient they are at attracting all sorts of moulds and dust mites?
But they pale into comparison with carpets. Yes, the lovely soft things you and your kids play on. Carpets have a bacteria rating of 4000 LSGL - 4000 times germier than a toilet seat.
Now you'd expect public loos to be less hygienic than most places and you would be correct.
They have a whopping 2 million bacteria per square inch and, when you flush the toilet, the germs can fly about 2 metres and live on for a couple of hours.
How many people will now move their toothbrushes and put the seat down when flushing?
We know cold will kill germs, so it comes as a bit of a shock that most fridges have traces of E coli in them.
Your kitchen sink is likely to have more bacteria in it than your bathroom and on that subject I must mention to my cleaner to be really scrupulous around the drain area - as this has a 5000 LSGL rating.
And clean out your pet bowl regularly, because in ones with a rim there can hide 400 times the loo seat of germs.
As you would expect, I have left the really gross bits until last. If you are a fan of re-usable shopping bags - and I am now changing my ways with these "green" items - they need to be washed regularly, otherwise they will end up with more fecal matter than your undergarments.
So what is the dirtiest most filthy thing in your house - apart from the floor in your teenager's room? It is the humble kitchen sponge, which crawls with 10 million bacteria per square inch. A LSGL of 2million.
After all that I need a drink - only I won't have it with ice from US fast food stores. A study of those ice chunks shows they have more bacteria than toilet water.
-richard@richardmoore.com.
Richard Moore is an award-winning Western Bay journalist and photographer