Greenwich households will start to get water meters fitted later this year.
Thames Water says the devices help people use around 12 per cent less water, reduce bills and protect future water supplies.
The company will write to all customers affected and preparation work will start from June with meters screwed in towards the end of the year.
Customers will have two years to adjust before being moved onto a metered account unless they wish to switch early.
Thames Water’s head of metering Steve Plumb said: “We all have a vital role to play in reducing demand for water, but first everyone needs to understand what they are using. That’s why we’re fitting smart meters across our region as by knowing more we can all waste less.
“By using smart meters we will be putting our customers in greater control of their bills, using the most advanced technology.
“As part of this project we are offering everyone a free Smarter Home Visit, which has been carefully designed to help customers prepare for the switch onto a metered tariff and to help them find simple, but effective ways to monitor and reduce their water use.
“Metering is the fairest way to pay for water because you pay for what you use, value what you pay for and as a result tend to use water more efficiently.”
Around 27 per cent of Greenwich homes currently have a water meter which will rise to 42 per cent by the end of March next year when they will be rolled out in flats.
For more information visit thameswater.co.uk