Matt Diehl, spokesman for the Anne Arundel's Department of Public Works, said about 20,000 county residents, most of them in the Brooklyn Park area, are served by the Baltimore water system. The county issues and processes customers' quarterly water bills and has not received complaints about billing errors, he said.
"We get water from the city," Diehl said. "It enters our system and mixes with our water."
The county bills all of its public water users, regardless of the source of supply.
"The city bills us and we bill our customers," he said. "Everyone is billed on the same basis by the county, regardless of where the water originates."
Diehl said there have been no reports of overbilling from utilities customers.
"If there were complaints, I would hear about them," Diehl said.
Baltimore officials said a nearly 40-year-old meter-reading system was a contributing factor after 38,000 households in the city and Baltimore County were found in a recently released audit to have been overbilled.
The audit evaluated 70,000 households over the past three years and found that 65,000 were likely overcharged. That system serves 400,000 customers in Baltimore and Baltimore County.
Baltimore Sun reporter Jessica Anderson contributed to this article.