Broadband users would much sooner have the water supply cut than lose internet access at home, research shows.
Internet access at home is now seen as more important than a water supply.
A survey of 1,000 people in London found 38% would be more concerned if their broadband stopped working than if they lost basic utilities like water and gas. Only 32% put water above the web on their list of household essentials.
Meanwhile, a dramatic 27% said they couldn't live without internet access. A quarter believed they'd only survive for 24 hours if they didn't have broadband at home.
Claire Sellick, from Infosecurity Europe, which commissioned the study, said: "Having an internet connection is part and parcel of our everyday lives, becoming more important than even heat and water at home.
"It does seem phenomenal, but shows just how dependent we are on the internet."
Separate research by Age UK has shown a growing proportion of Britain's over-50s can't imagine life without internet access.
A recent poll by the older people's charity found 78% of the nation's silver surfers believe their lives have been improved by being online.
Nearly a quarter of older web users said they feel closer to family and friends and 42% claimed they couldn't live without broadband.