Both emergency declarations set limits on some water uses, such as watering lawns and washing cars. Other activities were banned, such as washing sidewalks and filling ornamental pools and fountains.
``There was a marked change after the governor's declaration,'' said Gloria Gledhill, a spokeswoman for New Jersey-American Water Co. ``We think our customers are really trying to comply with the requirements.''
In July, New Jersey-American Water's average demand was about 60 million gallons a day. After Whitman's declaration, the average dropped to about 42 million gallons a day, Gledhill said.
Company officials were unable to say exactly where the large drop in water use was coming from.
In Philadelphia, the average demand from late June until the day Gov. Ridge issued the drought emergency was 329 million gallons a day. Since then, according to the city Water Department, the daily average has been 305 million gallons a day - a drop of a little more than 7 percent.
The Water Department serves nearly 1.8 million city and Lower Bucks County residents.
The Philadelphia Suburban Water Co. also has seen an average daily decline in water demand, from about 129 million gallons a day to 120 million gallons a day. The company serves 785,000 people in Chester, Delaware, Montgomery, Bucks and Berks Counties.
``It is a very marked decline right after the governor's order,'' said Donna Alston, a company spokeswoman.
Philadelphia Suburban pumped 136 million gallons a day into its system the day before the emergency declaration; 120 million gallons a day the day of the declaration; and just 115 million gallons a day the day after.
``The actual amount will vary from day to day based on a number of factors,'' Alston said. For example, water used by firefighters or lost to a water-main break will boost daily figures, as will the heat.
``When you have a lot of hot weather, that will affect water use,'' Alston said.
But even with the torrid weather, water-supply officials say they still believe there has been substantial conservation.
The temperature at Philadelphia International Airport reached 90 degrees 20 times in July, according to the National Weather Service.
The Philadelphia Water Department uses about 337 million gallons daily on days with 90 degree temperatures, said Joan Przybylowicz, a department spokeswoman. But from July 23 to 31, when temperatures averaged 94 degrees, the average water usage was only 305 million gallons a day, or 10 percent less than expected.