Plans to increase the number of homes with water meters in drought areas will be unveiled by the government. The move follows work by the Department for Environment, Food and Rural Affairs's Water Saving Group to identify long-term measures to protect the sustainability of the water supply, and comes as suppliers gear up for the possibility of a third dry winter.

Switching homes to meters, where customers pay for water used rather than a set charge regardless of consumption, can help to reduce the amount wasted by each household. But the number of homes with meters is increasing at a rate of just 2% a year.

Today, the environment minister, Ian Pearson, will launch a consultation on the extension of compulsory metering, which could come into effect next year. Under the proposals, it would be easier for water companies to apply for "water scarcity status", allowing them to impose metering. A map of "water stressed areas" will be drawn up by 2009 and used to introduce compulsory metering in regions with a history of supply shortages. The plan was set out in May in a paper by the Water Saving Group, which brings together representatives of the government, water customers, regulators and the industry.

The paper warned: "Proposals for compulsory metering in water company areas will be controversial and need to be open to public scrutiny. Due consideration needs to be given to the potential impact on customers." At present, 26% of households have water meters, installed at a cost of around £40. Evidence from trials on the Isle of Wight in the 1990s suggests they can help bring water usage down by 10%-15%. In March, Folkestone and Dover Water Services became the first supplier to be granted water scarcity status, allowing it to force meters on its customers.

By 2015 it plans to have 90% of the 65,000 households it supplies on meters, up from 40% this year. The meters will be installed free of charge, Other water companies in the south-east operated hosepipe and sprinkler bans during the summer months, and pressure on supplies is likely to grow as spells of dry weather increase and large numbers of new homes are created. Andrew Marsh, spokesman for the Consumer Council for Water, said the expected proposals were a "common sense" response to shortages of the type seen this year. But he said that any introduction of compulsory metering should be accompanied by "substantial" financial support for the less well off, who may lose out from the switch.

Mr Marsh said: "Hand in hand with any compulsory metering, we would want some sort of substantial financial support programme. "There has to be concern about larger low-income families who would need transitional support." According to the water companies' trade body, Water UK, October to March is a vital "recharge period" when underground water supplies should start to recover.

Colder weather and increased rainfall mean limited plant growth, saturated soils and lower evaporation levels, which means water is able to seep into underground aquifers. In March, the government ruled out compulsory water meters across the country, but said companies in water-stressed areas were likely to want to impose them on their customers.