City outlines causes of water-billing spikes, promises credits and independent audits

City utilities staff presented a technical update on problems that led to unusually large April water bills for many customers. "We pulled six years of source data, ran end‑to‑end tests and built analytics to flag anomalous usage," Rich Gagnon told the council, explaining the vendor change, the data migration and the analytic baseline used to identify problem accounts.

Gagnon said three factors explained most of the April increases: longer-than-normal billing cycles (55,400 customers received longer-than-30-day cycles, median +6 days), tiered rates that pushed roughly 16,700 accounts into a higher tier and 1,243 accounts with anomalous high usage requiring account-by-account investigation. He said the city had already identified about $250,000 in tier overcharges and about $202,000 tied to known anomalies, and that staff will credit affected accounts and seek a third‑party technical system audit. "We're going to go to independent validation," Gagnon said. "We pulled all the data and we will hand that out to an external auditor to verify the billing is happening correctly." The council asked for regular status updates and for the city to notify affected customers under review.

Staff also showed that deploying newer digital meters reduced the historical gap between pumped and billed water (from about 31% historically to roughly 1.5% in the most recent period), meaning the city is billing a greater share of what it actually pumps. Gagnon said he expects three to four weeks to investigate the 1,243 flagged accounts and that staff will automate the analytics to detect issues proactively going forward.