Madras public works officials are trying to determine where more than a fifth of the water purchased by the city is going.

A contract engineer hired to update a water master plan for the city noticed the amount of unaccounted water increasing from 2009 to 2012, with 22.4 percent going unaccounted for in 2012.

“That’s high, but it’s not unreasonably high,” said the contract engineer, Hayes McCoy of H.A. McCoy Engineering & Surveying in Redmond.

Madras buys water from the Deschutes Valley Water District and then sells it to city customers. In 2012 the city bought 214 million gallons of water from the water district, but meter records show the city only sold 151 million gallons to customers. That means 29.4 percent of the water the city bought from the water district was used but not sold to customers.

McCoy estimates 7 percent of the water was used by the city itself, at parks and city buildings, bringing the total percentage for unaccounted water to 22.4.

There are two reasons water typically goes unaccounted for — leaks or inaccurate meters. McCoy said water system managers around the state try to keep unaccounted water to about 15 percent.

Other sources for unaccounted water could be firefighting, street cleaning and construction, said Raquel Rancier, senior policy coordinator with the Oregon Water Resources Department. She said it is normal to have unaccounted water in a city.

“In any water system, there will be a difference in the amount of water produced and the amount of water sold to customers,” she said.

While the city was aware there was unaccounted water being used in Madras, the amount McCoy discovered came as a surprise, said Keith Bedell, utilities supervisor with the Madras Public Works Department. He said the department wants to figure out where the water is going, but so far it hasn’t found an answer.

“We are going to investigate more,” he said.

Like McCoy, Bedell said the main reasons for water to go missing are unknown leaks and inaccurate meters.

“We have older meters that could read lower than new meters,” Bedell said. The city provides water to about 920 metered accounts.

The next step is for city workers to start checking older meters to see if they are the culprit for the unaccounted water, said Madras Mayor Melanie Widmer.

The Deschutes Valley Water District surrounds Madras and supplies water to newer parts of town, said Ed Pugh, the district’s general manager. The water district has sold water to the city for about 20 years.

Pugh said he feels for public works officials as they search for the reason behind the unaccounted water because it could be more difficult to find leaks in town than out in the surrounding fields.

“I think what is going on is the geology of Madras,” he said.

The town sits atop silt at the bottom of a basin, Pugh said, so water from a leak likely soaks into the ground and disappears. The fields around town have about 11⁄2 or 2 feet of top soil over hardpan. Leaks there typically result in water bubbling up from the ground.

— Reporter: 541-617-7812, ddarling@bendbulletin.com