About 4,000 Waterloo taxpayers had a monthly property tax payment of over $300 deducted from their bank accounts on Monday, over a week earlier than expected.

The ease of paying bills electronically and automatically has become a popular choice for many people. But the early withdrawal, which should have occurred on Feb. 1, could end up costing some people cash and potentially even damage their credit ratings.

Waterloo homeowner Wade Sanderson says he checks his bank accounts everyday and was shocked to see that the city had taken an early tax installment.

"It's pretty significant - it's hundreds of dollars," he says. "It could impact people's financials and if they aren't expecting it, they might have bounced cheques or go into overdraft."

Sanderson says he called the City of Waterloo as soon as he noticed his money was gone, "They were apologetic and they got back to me right away. I would hope that if they did cause any fees, they would look into that."

The city says it made an honest mistake and that it was a human error and the money has already been returned to taxpayers.

Director of Revenue John Morrison says "the clerk made an error unintentionally."

But Narima Whitman, a manager at Your Neighbourhood Credit Union, says the implications can be significant, especially for someone with a marginal balance in their account.

That includes an impact on their credit rating and the possibility they could have to pay fees or interest on the amount withdrawn.

Morrison says the city has taken steps to ensure it doesn't happen again and that they will make good on any associated costs taxpayers may incur. He says those affected by this incident will receive a letter in the next few days explaining what happened.