Aquarion Water Co. officials, facing water consumption rates during this week's heat wave that are "through the roof," are urging customers to voluntarily conserve water because distribution lines, tanks and pumping stations are running at their limits.

Westport is one of the towns served by the regional utility where water usage is particular concern, officials said.

"We're afraid that if people don't conserve, that there might not be enough water for everybody," said Aquarion spokesman Bruce Silverstone.

Tuesday went down in history as the day that Aquarion delivered its greatest amount of water in a 24-hour period to its overall service area, Silverstone said. The company delivered 140 million gallons of water that day, the most it ever has in its 153-year history. This compares with about 80 to 90 million gallons consumed on a typical day.

"We have plenty of supply ---- the reservoirs are fine," Silverstone said. "But because people are using so much water, our water tanks, which we have all over, aren't refilling at night like they're supposed to." He explained that these water tanks normally are supposed to refill to the top overnight. Because of the high consumption rates, "this wasn't happening," he said.

In addition to Westport, the problem is most acute in Ridgefield, Stamford, New Canaan, Darien and Greenwich because those communities are "downstream" from the company's major reservoirs.

"The pipes get smaller when you go in that direction, and we have tanks down there that are low," he said.

The water use is being propelled by the punishing heat wave gripping the Northeast with triple-digit temperatures and steam-bath humidity. The National Weather Service says that the hot weather will continue well into next week. There might be a bit of a break Saturday when thunderstorms are expected to erupt. But after that, the tropical weather will return.

Aquarion officials said that water pressure for firefighting remains plentiful. "Don't worry about that," Silverstone said.

For much of Tuesday night, homeowners in a section of Shelton found themselves with either dry taps or with low water pressure after a pumping station failed at about 10 p.m. That problem was fixed by about 9 a.m. Wednesday. There was also a water main break on Bridgeport's State Street Extension on the city's West End Wednesday morning.

While Aquarion stopped short of declaring an emergency, the utility did outline a number of measures for customers to take in order to prevent the problem from worsening.

They called for people with odd-numbered addresses would water their lawns and gardens on odd-numbered days, from 5 and 9 a.m. or 7 to 9 p.m. People with even number addresses would water during those time periods on even-numbered days.

Though new lawns need watering regularly, Aquarion asked customers with established lawns to defer watering for a week. Washing boats and car should be deferred for at least a week, according to spokespeople at the company.

Aquarion Water Co. serves approximately 580,000 people in 39 communities throughout Connecticut. It is among the seven largest investor-owned water utility companies in the U.S., and the largest in New England.