In article , Mary
Fisher wrote:

How do you know?

It's my business to know - but I won't tell you what my business is.
However, most of the information is published by Ofwat, Defra, the
Environment Agency, the WRc, the Water Demand Management Group, the
water companies, WaterUK, CCWater, Waterwise, Exeter University,
Imperial College London, the Institute for Public Policy Research and
various associated technical bodies and NGOs.

Here's a quote from CCWater (formerly the Consumer Council for Water):

"Current metering policy is inherently inefficient as, with the
exception of new developments, installation is piecemeal as companies
react largely to notifications of change of occupation or to customers¹
requests to install meters. This limits the development of smart
metering thereby reducing the prospect of innovative tariffs. If
companies introduce tariffs that vary according to the stress on supply
and increase according to consumption above a certain threshold, then
consumers will be able to adjust their water use on a rational basis.
Such tariffs would need safeguards to protect vulnerable groups and
those on low incomes."

Information on Kent's seasonal tariff trial can be found at
http://www.savingsontap.co.uk/tariff.html

For the rest, Google "identiflow"