Many communities already are moving in that direction, although the impact of the new regulation is unclear.
The potential change comes in a section of the proposal dealing with local utilities that apply for permits or changes to permits allowing them to draw water from rivers, lakes or other bodies of water. All water companies eventually could fall under the rules when they re-apply for permits.
According to the draft of the plan, which must be approved by the Georgia Water Council and sent to the General Assembly for an up-or-down vote, utilities without a good water conservation record must instate certain practices to gain approval.
Among the practices is a way of billing customers the plan refers to as "a tiered, conservation-oriented structure," which charges a higher rate to customers who use more water. The plan calls for those kinds of changes to help control demand on water.
According to the proposal there are many ways to manage water consumption and encourage conservation, including "conservation water rates, limiting outdoor watering, and regular audits of public water and irrigation systems."
Margaret Doss, the water quality manager for the Columbia County Water Utility, said the department has billed residential customers according to how much water they use for close to a decade.
After paying a base rate of $8.72, Ms. Doss said, a customer who uses less than 10,000 gallons of water a month pays $1.79 per thousand gallons. Customers who use between 10,000 and 30,000 gallons pay $2.48 per thousand gallons, with rates increasing until those using more than 50,000 gallons pay $4.88 per thousand gallons.
"That encourages you to use less water because you're going to pay more for it," Ms. Doss said.
Ms. Doss said the rates do appear to be having an effect, particularly on customers using more than 30,000 gallons of water.
"Once people realize that that rate structure is there, they'll pay attention to what they're doing," she said.
Others, even in communities where there are tiered rate structures, are skeptical.
Henry Jue, the director of the Savannah Water and Sewer Bureau, points to Americans' use of such commodities as gasoline even as prices go up. Savannah also charges customers who use more water a higher rate.
"Unless it gets real cost-prohibitive, I don't think it's going to slow usage," Mr. Jue said.
Even so, some utilities like the idea enough to try it, said Steve Dorsch, the water conservation coordinator for Athens-Clarke County.
Mr. Dorsch said Athens officials have been working for months on a tiered rate structure that could be in place by 2008.
"It you want to use more, that's fine," Mr. Dorsch said, "but you're also going to pay a little bit more."
Reach Brandon Larrabee at (678) 977-3709 or firstname.lastname@example.org.