When Les Waas, an investor in Philadelphia Suburban Corp., paged through the company's 1994 annual report, he was impressed by what he saw.

The water utility had used a series of charts to represent its revenues, net income and book value per share, among other results. Each figure was represented by the level of water in a glass. Each chart showed strong growth.

Then Mr. Waas looked a little more carefully. The bars in the chart seemed to indicate far more impressive growth than the numbers beneath them. A chart showing the growth in the number of Philadelphia Suburban's water customers, for example, seemed to indicate the company's customer base had more than tripled since 1990. But the numbers actually increased only 6.4 percent.

The reason for the disparity: The charts don't begin at zero. Even an empty glass in the accompanying chart would represent a customer base of 230,000.

``I don't think this is right,'' says Mr. Waas, 74 years old. ``People look at graphs for a quick representation of the information being presented. This is a graphic distortion.''

Representatives of the utility say they don't believe the company has done anything wrong. The graphs were designed to easily illustrate the company's growth to its shareholders, many of whom are also its customers, explains Chris Franklin, the company's senior manager of corporate and public affairs. Financial analysts, Mr. Franklin says, would be more inclined to look at the numbers, which are provided.

``We feel very comfortable that the way the charts are portrayed is accurate and acceptable,'' he says.

Mr. Waas says he is perfectly happy with his investment in the company, which had a good year. But he does have another complaint. ``It is also unfortunate that they decided to make the water in the glasses purple,'' he says. ``I like my water clear and pure.''