Washington Suburban Sanitary Commission representatives held a second meeting for the community to explain the water main project. The pipe will be carved through much of Montgomery's downcounty and will provide water to Prince George's County, as well as help to maintain water pressure in portions of Wheaton and Silver Spring.

About 60 people attended and listed concerns ranging from loss of trees to construction noise to traffic snarls.

"When I heard about the project I just saw the potential for some incredible disruption," said Mary Arndt, who lives in the Tilden Woods neighborhood. "We're sensitive to the need, but we're not going to benefit at all from this."

The main would fulfill water needs for the projected population growth in Prince George's. It would also help maintain water pressure in parts of Wheaton and Silver Spring. All of those areas could see a dip in water pressure if the main is not built. If pressure is not high enough, officials said, fire hoses won't operate correctly, which puts everyone in danger.

"We need to enhance reliable water supply to Prince George's County," said John Mitchell, project manager at WSSC, explaining that the commission's goal is to have the new main constructed before customers experience reduced water pressure.

All nine of the routes begin near the Montgomery County bus depot at the intersection of Tuckerman Lane and Interstate 270. The new pipe will connect to an existing main that comes from the Potomac Water Filtration Plant on the river. From there, depending on the route chosen, the pipe will run roughly 5 1/2 miles through Bethesda, Rockville, Garrett Park and Kensington before ending at Stoneybrook Road near the Mormon Temple.

There are three methods WSSC could choose to install the pipe -- each with benefits and drawbacks. The less expensive method would strip more land than the alternative, which would save more land but cost millions of dollars more.

The first involves clearing about 60 acres of trees and digging a trench to lay the pipe. After it is installed, the pipe would be covered with dirt.

The second, more expensive option, involves clearing nine acres to dig holes up to 350 feet to lower machinery into the ground so the pipe can be installed. A third option would use a combination of the two methods.

WSSC provides drinking water and sewage services to Montgomery and Prince George's counties. The pipe through Montgomery County is a necessary link in the chain of pipes that provide water to Prince George's customers.

Despite understanding a need for the pipe, residents question how WSSC will go about installing it.

Arndt and others said they are worried about the trees that will be lost if WSSC chooses to dig a trench to lay the pipe. But they are also worried about how their lives will be affected once the project is complete in 2010.

Arndt questioned the proposed alignments that run through Tilden Woods, asking why WSSC would consider those alignments when a route running south along I-270 would be less disruptive.

But Liz Dane asked about who it would be less disruptive for.

"I live along I-270," said Dane, who is also president of the Grosvenor Park Townhouse Condos.

Later, Dane said she and her neighbors are worried that if WSSC chooses the alignment near her neighborhood, it will lose the last stand of trees that shields it from the noise of highway traffic.

"If the trees go, we've got 75 units that will be on 270," she said.

She said she preferred the underground tunnel method because it would save the trees.

"I'm happy that WSSC is talking to the community, because that's the first step in any working relationship," said John P. Scott, who also lives near Tilden Woods. "But my primary concern is the trees."

Steve Miller, who lives off Tuckerman Lane, recommended that WSSC officials take a straw poll of meeting attendees to see if any supported digging the trench instead of tunneling underground.

"Open cut might be the most economical, but it's also the most disruptive," he said.

No poll was taken, but Mitchell said he was glad to hear the feedback.

WSSC officials never finished their presentation as the meeting dissolved into a question-and-answer session with officials assuring attendees that they wanted to hear from everyone. As part of the planning for the process, WSSC is forming a citizens advisory committee of 20 to 25 residents to discuss the potential alignments and help choose one.

It hopes to have an alignment chosen by August, with construction beginning in summer 2007 and ending in summer 2010. To become a member, people can fill out cards at one of the public meetings, or contact the WSSC hotline at 301-206-8184.