According to the CDC, it takes less than a minute for E. coli to be inactivated if chlorine levels are adequate, about 16 minutes to control Hepatitis A virus, about 45 minutes to kill off the Giardia parasite and over 10 days for a Crypto parasite.

CNN: Yuck! What's in your pool water

"Many firms could be in for a nasty shock by failing to give themselves adequate legal protection when doing e-business, " said the London chamber's acting chief executive Peter Bishop.

BBC: E-tailers 'breaking law'