NU'UANU — Girl Scouts Caroline Kodama and Mikayla McCarthy got a lesson yesterday on how to find and fix a leaky toilet.

The Girl Scouts, in partnership with City Mill Home Improvement Centers and the Board of Water Supply yesterday kicked off the 18th annual Detect-A-Leak week that runs through Saturday.

Frank Suster, City Mill facilities manager, showed the two Scouts where the water main was located in front of the Girl Scout hale on Wylie Street and told them how to figure out if you have a leak.

"If all the water is turned off in the house and this dial is spinning, then you have a leak somewhere," Suster said. "It could be a faucet, a toilet, a hose bib or, worse-case, an underground pipe."

Fixing leaks saved customers more than 518,000 gallons of water and $1,525 last year, said Su Shin, Board of Water Supply spokeswoman.

"This is all about public education and outreach," Shin said regarding Detect-A-Leak week. "We wanted to expand it and do it with the schools, and it was a nice fit with the Girl Scouts."

Suster dropped a blue dye tablet into the tank of the toilet. If any of the blue colored water seeps into the bowl, Suster told the Scouts, then you have a leak and the most likely culprit is the flapper inside the tank.

"This is interesting," said the 9-year-old Mikayla. "I see the slime on that flapper. Eeewww."

Caroline, also 9, was interested in fixing leaks as much as she was in learning how to identify them.

"If you waste too much water, you'll have a big water bill," Caroline said.

The Scouts will receive a Water Everywhere patch as proof that they learned something yesterday.

"You can't rely on the rain to all the time to fill up the water supply," Caroline said. "So we need to be smart about water use. We need to think about the future. When our kids have kids, we want to make sure we have water for them."

Using the Scout hale as the backdrop for the launch of Detect-A-Leak makes perfect sense, said Tammy Yamanoha, Girl Scouts director of communication. One of the Scouts' basic tenants is to leave a place in better shape than you found it.

"We always emphasize sustainability," Yamanoha said. "We hope the girls will take away the tools on how to conserve. They've learned that what they do today will affect the future."