"In some cases we have to deal with the legal issue of bankruptcy," Kocher said. "We also understand that there are third-parties involved — employees, tenants, tourists and even animals [in the case of the Zoo], and we are sensitive to these issues as we deal with the outstanding bills."
Those who have large delinquent bills listed on city records offered a variety of explanations.
Greg Euston, a spokesman for W.R. Grace, said the company began having concerns about unusually high bills in 2009 and started "negotiating with the city over the true amount owed." W.R. Grace recently agreed to pay $2.2 million, he said, and its balance is now $475,000.
He pointed out that the city had agreed to replace the Curtis Bay plant's water meter.
Whitney Burger, energy engineer at the Baltimore VA Medical Center, said she has been disputing the city's bills for more than five years. She says the center's wastewater bill, listed at about $800,000 on records, has multiplied over time — despite being paid.
Since 2006, she said, the city has not credited the federal hospital's account for 15 of its payments, and she provided documents of the payments for The Sun to review. The city frequently sends the center turn-off notices, but never acts on them, she said.
"It's frustrating," Burger said. "I'd like to get it resolved. It's stressful when we receive turn-off notices. We want to work with the right person to get this taken care of."
Lawyers for RG Steel did not respond to requests for comment. City Solicitor George Nilson said the city filed as a creditor against the bankrupt former steel giant on June 12 and hired the law firm Venable LLC to attempt to recoup the funds. The steel company has acknowledged in court documents owing about $2 million to the city's Department of Public Works.
At the zoo, executive vice president Nancy Hinds said the nonprofit has entered into a payment plan. She said zoo officials first contacted City Hall over the winter about their spiking water bills and adjustments were made to the zoo's account.
"We were concerned with how high the water bills were," Hinds said. "We have been working with the city and the Department of Public Works. They couldn't have been nicer and more cooperative."
Officials at Fort McHenry, University One Condominiums and Baltimore Marine Centers did not respond to repeated requests for comment. The executive director of Broadway Market declined to comment.
City auditor Robert McCarty said his office analyzed specific complaints about the water-billing system and did not look at the issue of overdue commercial accounts.
He noted that the audit found that nearly one-third of homes in Baltimore and Baltimore County with new meters had not received any bills over a three-year period. Of the 3,406 households that received new meters during 2008-2010, nearly a third did not receive bills, according to the audit.
"We're aware that not everyone is paying timely," McCarty said.
City officials have outlined a broad, long-term effort to address billing problems attributed to faulty water meters, an outdated computer system, human error and, in some neighborhoods, meter readings allegedly fabricated by two employees who no longer work for the city.
Councilman Bill Henry said businesses are going through the same ordeal of inaccurate water bills that residents have been experiencing — and many suffer from higher-than-normal water bills. "It's just on a magnified scale," he said.
Stokes said he believes a more wide-ranging audit of the water-billing system is needed, noting that the auditor analyzed about 70,000 out of the city's 410,000 accounts.
"How can a citizen on a fixed income who owes $400 on a bogus bill be threatened with her house being taken from her, while a business is allowed to owe $6.7 million?" he asked. "We need to open this up and do a full comprehensive audit."
City Councilwoman Mary Pat Clarke took issue with the uncollected funds from large businesses, saying the money could have been used to offset some of the water rate hike.
"We've been through very hard times and worked with the water department through a nightmare of inaccurate billing, spiked billing," Clarke said. "I'd like to see this money collected before we raise anyone's rates again."