A New Orleans Sewerage & Water Board consultant has recommended that the utility once again allow its billing software to calculate what customers should owe in cases where their meter isn’t read, a practice that was suspended last year when it appeared to be a key factor leading to widespread overbilling.

One in five customers get estimated bills each month, representatives of Baton Rouge-based utility consultant Utiliworks told the S&WB’s board of directors at a meeting Wednesday. But generally, the firm said that after more than a year and a half of serious billing issues, the utility’s systems and staff are now working fine.

The S&WB has had problems with its billing software, designed by the Canadian company Cogsdale, since it rolled out the current system in late 2016. But things reached a fever pitch in the latter half of 2017, with thousands of customers receiving vastly inflated and obviously incorrect bills.

The S&WB has never provided a comprehensive accounting of exactly what went wrong with the billing system or why so many customers received inflated bills. As the debacle played out over the course of the past year and a half, officials have variously pointed the finger of blame at the Cogsdale software, a lack of training for employees and widespread human error.

But as officials, consultants and customers looked for answers, one issue remained at the forefront as a likely culprit: problems with the formula that estimated bills, based on past usage, when a meter could not be read.

To combat that issue, utility officials changed course in the fall and began charging a flat amount per month when an estimated bill had to be sent out. Since then, major problems with bills appear to have tapered off, though not ended.

The flat rate, however, is based on the assumption that a customer will only use 100 gallons of water per day. The average residential customer actually uses 171 gallons a day and the typical commercial customer uses 1,523 gallons a day, said Nicole Griffin, a senior manager with Utiliworks.

That means that for the most part, the estimated bills are too low, Griffin said. About 5 percent of customers end up with estimates that are too high, she said.

S&WB officials suggested that switching back to individually estimated bills rather than using a flat rate would not only bring more money into the financially precarious utility each month but also reduce complaints that come when the meter is actually read.

Customers often “call in and complain about a high bill because they had multiple months of an estimated bill” and their total when they get a bill based on an actual reading then is much higher to account for many months of water actually used, Chief Financial Officer Yvette Downs said.

The Sewerage & Water Board did not respond to a series of questions about the company’s report or its recommendations.

Utiliworks was brought in last fall by new Executive Director Ghassan Korban to examine the S&WB’s billing system from top to bottom. It sent its people out with S&WB meter readers, sampled 383 of the utility’s 136,000 accounts for accuracy and examined the settings on the billing software. Its conclusion was that everything was now fine.

“The way the system is configured is correct, kind of in line with industry best practices,” Griffin said.

The company did not say what it thought had gone wrong in the past.

Council members' offices said Wednesday they have seen a slowdown in complaints about incorrect S&WB bills, though problems persist.

Councilman Jay H. Banks, who sits on the S&WB, said there have been improvements but he wasn’t yet prepared to claim victory.

“I’m pleased with the fact that at least we’re getting to the bottom of this because it’s obviously a serious problem,” Banks said. “By no means am I ready to spike the ball yet, but at least we’re on the road to get this fixed.”

One major problem Utiliworks found is that 20 percent of meters cannot be read each month. Each of those meters would get an estimated bill.

“Our recommendation is first and foremost to work on that issue because 20 percent is a huge number,” Griffin said.

While half those meters are only temporarily blocked — by parked cars, flooding or other problems — the rest can’t be read because they are broken, have scratched lenses or are covered over by tree roots, Griffin said.

It can take anywhere from several days to several months to fix those more serious problems, Korban said.

Follow Jeff Adelson on Twitter, @jadelson.​