A 25,000% increase? Errant water bills shock some Philly residents.

When the Facebook reports started rippling and she found that some of her Point Breeze neighbors were getting outrageously high monthly water bills — one of them over $7,000 — Maureen Molinaro thought she better check hers.

It wasn’t $7,000, but $12,000, more than 25,000% higher than her typical $46 monthly charge. And that wasn’t the worst of it. Nearby, Megan DiPasquale got hit up for $14,851.96, what she called a “shocking number,” given that she typically pays $35.

“It’s crazy,” Molinaro, who lives near 23rd and Wharton Streets, said Thursday.

No, the Water Department has not installed gold-plated pipes, nor is it dispensing Dom Perignon through the faucets.

It turns out that “an issue with the billing files” set off a “cascade” (pun intended?) of inaccurate bills, said Brian Rademaekers, Water Department spokesperson.

Errant bills might have been sent to as many as 17,000 customers in 19 zip codes citywide, he said.

He added the department was working expeditiously to correct the errors and get the system straightened out. In the meantime, it has put a stop on all automatic payments for affected customers.

» READ MORE: Bracing for Philly’s 17.6% water rate increase? Here’s how to be heard in the online public meetings.

Rademaekers said that outsize e-bills were “brought to the attention” of the department on Wednesday and that it still was assembling a list of those affected. It had not yet been determined how many, if any, of the errors appeared in the mailed paper bills.

“We understand this error caused stress and frustration for these customers, and we are working to resolve the situation as soon as possible,” he said in a statement. In the meantime, affected customers can call 215-685-6300 between 8 a.m. and 5 p.m.

DiPasquale, who works in finance, said she was “upset” that the department would put the onus upon customers to report the errors. “If my system was suddenly sending invoices over 400 times larger than normal to our customers, I would notice pretty quickly. I wouldn’t need anyone to bring it to my attention.”

Rademaekers said the department expected “the process of correcting the bills to begin as early as Friday and we will continue to work until all issues are addressed.”

In the meantime, he said, “no one is going to get a lien on their house or anything like that.”

Said Molinaro, “As long as you don’t expect me to pay $12,000, we’re good.”