PROVIDENCE — Rhode Island’s drinking water supplies should become more dependable over time, thanks to a complicated piece of legislation that appears destined for passage soon by the General Assembly.

The Water Use and Government Efficiency Act of 2009 was unanimously approved by the House Environment and Natural Resources Committee Thursday night and is probably scheduled for a vote by the full House this week.

The legislation was passed by the Senate in May. It has been supported by several state agencies, as well as by a diverse array of environmental advocates and water supply companies and districts. No opposition was voiced in recent weeks.

The legislation arose more than three years ago when concerns were raised over the adequacy of drinking-quality water for Amgen’s pharmaceuticals plant in West Greenwich and for the Quonset Point business park in North Kingstown.

While Rhode Island generally has plenty of drinking water, particularly in urban areas supplied by reservoirs, there have been repeated shortages in many outlying areas, where much of the water comes from wells.

The problem is always worse in the summer, when demand for watering lawns and washing cars sends usage soaring, at the very time that supplies are least plentiful. Some ponds and streams have been harmed by losing water as water supply wells pull water from aquifers.

One hot spot is in North Kingstown, where Quonset Point and two local water companies all draw from the same aquifer, creating a demand that has dramatically lowered the Hunt River in some summers. This summer, a pilot conservation program will be launched in the area to determine which conservation measures work best.

A group called the Coalition for Water Security has worked for three years to have the General Assembly enact legislation that would please all the diverse interests involved, particularly state agencies, water suppliers and environmental activists.

Sheila Dormody, the group’s coordinator, said the bill will give the state better oversight over its water resources while also maintaining the state’s quality of life by protecting natural resources.

It mandates that the state’s Water Resources Board sets targets for water conservation.

And it gives suppliers the authority to set rates to promote conservation. Such rates could charge more per gallon when excessive amounts are used, or set seasonal rates to discourage heavy use in the summer.

The bill also allows water suppliers to set up enterprise funds so they can set aside cash to spend on infrastructure improvements.

The coalition issued a statement Friday encouraging the House to approve the bill because “it will help Rhode Island manage its water supplies more efficiently, and can provide an economic stimulus for the state, giving economic development efforts a boost while still protecting the natural resources that make the state a preferred place to live and visit.”

plord@projo.com