A new policy instituted by the Honolulu Board of Water Supply ensures that no customer will receive more than two consecutive bills based on estimated usage, Manager Ernest Lau told a City Council committee Wednesday.

The semiautonomous city agency has also instituted other improvements to ensure there is no repeat of the billing problems that occurred in 2013 when nearly 4 out of 5 of its 166,000 customers received at least one bill that was "estimated" — meaning they were undercharged or overcharged for at least a month. Customers who contacted the Honolulu Star-Advertiser showed bills stating they owed as much as $3,000 because they had been undercharged over as many as seven billing periods.

But that’s a thing of the past, Lau told the Public Works and Sustainability Committee.

The agency "has already implemented within the billing system criteria to ensure that only two consecutive estimated bills can be issued by the system," Lau said. "If the system attempts to issue a third consecutive estimated bill, it is investigated by either a customer service representative, pre-audit clerk, water service investigator or a combination of staff to efficiently resolve any billing or related issue for our customers."

The new policy began at the end of last year, Lau said. Previously, the accounts of customers receiving six consecutive estimated bills were flagged for review, he said.

Lau’s testimony was in response to Resolution 14-19, which calls on the board to investigate instances when a customer receives more than two consecutive estimated bills "to ensure the ratepayer is not being charged due to a billing error or water main leak." The resolution also calls on the agency to give a customer "prompt notice" that they are receiving estimated bills.

Lau said the board has also changed its billing statements to ensure that it is "clearly stated" if the amount owed is based on estimated usage.

While board officials have repeatedly downplayed the impact of a customer receiving a single estimated bill, the board has not calculated how many customers received two or more consecutive estimated bills during last year’s turmoil.

"That would take a lot of effort on our part, and rather than focusing staff resources on addressing what happened in the past, I’m having them working on what is occurring right now and keeping the system stable," Lau said.

After fixing the technical issues that caused the high number of estimated bills, no more than 3,000, or 2 percent, of its customers are now getting an estimated bill each month, Lau said.