(IDG) -- A new report released by two watchdog groups claims that most U.S. water and sewage utilities aren't prepared to handle the year 2000 rollover.

But executives from industry associations dispute those charges, claiming that the data being used is outdated and attacking the methodology used to draw those conclusions.

The report, issued by the Natural Resources Defense Council (NRDC) and the Washington-based Center for Y2K & Society, states that only 20% to 45% of drinking water systems were Y2K-ready as of June 1999. However, a spokesman for the Denver-based American Water Works Association said 85% of its 4,200 members -- which are responsible for 67% of the drinking water available in the U.S. -- had completed their Y2K remediation efforts by July.

Meanwhile, the NRDC report claims that a July survey found that only 4% of U.S. wastewater facilities were Y2K-ready. A spokesman for the Association of Metropolitan Sewage Agencies (AMSA) in Washington called the NRDC report "unnecessarily alarmist" because, in his opinion, it doesn't accurately portray the Y2K readiness of AMSA's 239 members.