To blame persistent billing errors that affected nearly 80 percent of Oahu’s water customers on a "technical glitch" defies imagination, but that is essentially what Honolulu’s Board of Water Supply has done.

The semiautonomous agency has largely solved its billing debacle on the backs of its customers, and must be held to a higher standard should these problems recur.

If the agency does generate widespread billing errors in the future — whether due to new computer software, dead water-meter batteries or the full moon — customers should not be left holding the bag, as they were this time.

The agency’s seven-member board of directors must inject accountability into an agency that clearly lost control of its billing system for a time, gave evolving, unsatisfactory explanations as to the cause, and failed to offer the level of customer service necessary to stem a basic loss of trust in the agency that manages Oahu’s municipal water supply — an essential natural resource.

To restore a sense of confidence, the Board of Water Supply (BWS) should immediately pledge not to back-bill customers if widespread billing errors occur in the future, and should implement a fair, efficient and transparent dispute process for customers.

Honolulu City Councilwoman Kymberly Pine has proposed a charter amendment that would put this issue to voters at the next election, effectively barring the BWS from revising customers’ bills after the payment cycle.

So drastic an action would be unnecessary if the BWS would simply step up and do what’s right: Discontinue the practice on its own, by committing to superior customer service and to the timely, accurate processing of water users’ bills.

Competent management could make this issue moot.

The agency’s latest — and we hope full — explanation for why roughly 132,800 of Oahu’s 166,000 water customers received incorrect bills during the first nine months of 2013 focuses on a "technical glitch" related to the convergence of two software systems.

The agency reports that there were four primary causes for a spike in estimated bills — as compared to those based on actual water usage — and all could be traced back to the glitch that occurred when the agency tried to upload information into its new customer service software based on data collected by its older meter-reading software.

According to the BWS, other, related problems — such as dead water-meter batteries and a shortage of meter readers — compounded the impact of the glitch, to the point that nearly eight out of 10 customers received bills that only estimated water charges, based on past consumption or on what their neighbors were using.

Some of those estimates were off by hundreds or even thousands of dollars, and ratepayers were back-billed for large, accrued amounts months after they thought they’d paid their bill in full.

In outlining the various issues for the agency’s governing board, a BWS spokesman acknowledged that while the agency was able to identify the root cause and make the necessary fixes, it doesn’t know exactly why the malfunction occurred, or even whether it was due to a software flaw or to human error.

Absent this insight, and the attendant sense of accountability, there’s little assurance that another "technical glitch" won’t wreak similar havoc in the future.

That’s why discontinuing the practice of back-billing is so important: Knowing that it must get customers’ bills right the first time or pay for its own mistake would force the agency to run a tighter ship.

The Honolulu Board of Water Supply clearly needs that incentive, and should welcome it as a mea culpa to its customers and a pledge to do better.