Assemblyman Jeffrey Dinowitz is calling on the community organization that serves as the Van Cortlandt Park filtration plant's official watchdog to join him in demanding an investigation into the project's ballooning costs.

Speaking at the first Community Board 8 meeting of the season on Sept. 11, Mr. Dinowitz, along with fellow filtration plant foe Gary Axelbank, brought the board up to date on what they say are "growing scandals" at the site.

Two Board 8 members, Tony Cassino, chairman, and Saul Scheinbach, chairman of the environment and sanitation committee, sit on the Croton Facility Monitoring Committee.

That committee will meet for the first time this season today, Thursday, Sept. 20, and Mr. Dinowitz and Mr. Axelbank said they wanted to ensure that its members, and the community, had the necessary information before meeting with representatives of the city Department of Environment of Protection, the agency overseeing the plant's construction.

Back in May, Mr. Dinowitz asked the city Department of Investigation to launch a probe into the DEP's handling of the plant's construction, after learning the price tag had skyrocketed from $1.3 billion to more than $2 billion. He puts the actual price at closer to $3 billion.

He and community activists have argued that the DEP misleadingly excludes $697 million from its cost estimates, ignoring the contract for the plant's design, the construction management costs and the mitigation funds allocated to Bronx parks.

When these costs are factored in, the assemblyman said, Van Cortlandt Park is no longer the cheapest site. Cost was the primary reason the officials gave for choosing to build in the park.

Inspectors from the Department of Investigation attended the May 17 Croton Facility Monitoring Committee meeting, and said they would keep an eye on construction costs and practices for the remainder of the project.

Over the summer, Mr. Dinowitz met with DEP Commissioner Emily Lloyd, who attributed cost overruns to inflation, but Mr. Dinowitz remained unconvinced. In August, he met with representatives from the Department of Investigation to share his findings.