Audit finds Gilbert water meters accurate for 97% of accounts; town and auditor outline fixes for 2.9% of anomalies

Kimley Horn, an engineering firm hired to audit Gilbert’s water metering system, told the Town Council on April 7 that its review of physical meters, radio transmitters and six years of billing data (Jan. 2020–Dec. 2025) found no systemwide failure but did identify targeted anomalies affecting roughly 2.9% of active accounts.

“Today we can validate that there are no systemwide issues,” Kimley Horn project manager Tyler Kay said, adding that “97.1% of all accounts were recording usage and billing accurately during the audit period.” The auditor said the most common problems were multiplier configuration errors, billing code mistakes, rounding and isolated meter accuracy issues.

The audit tested a statistically representative sample of the town’s meters and radios and shipped 451 meters for off‑site laboratory testing, achieving a 98% confidence level for those samples. Kimley Horn reported that radio transmitters performed well (over 99% reporting correctly) and that meter failures were largely related to age rather than manufacturing defects.

Kimley Horn summarized financial impacts for affected residential accounts: customers who were overbilled averaged about $125 total over the six‑year window (about $25 for a typical five‑month exposure), while underbilled accounts averaged about $110 (roughly $22 for five months). The firm emphasized that many flagged accounts had already been corrected by the town and that some anomalies produced no financial effects.

Town finance director Hawin New Hansen said staff had received a preliminary version of the audit and would not wait for the final report to take action where problems were identified. “We will be carefully reviewing the full audit findings and validating them to ensure we fully understand the data on an individual account level,” he said. Hansen said likely next steps include issuing credits where overbilling occurred, making consistent adjustments for underbilling, tightening multiplier checks and improving customer communications.

Council members and residents pressed Kimley Horn and staff on how many accounts remained outstanding, timing for the final report and mechanisms for customers to request an efficiency check. Kimley Horn said the final report would be posted at khwatermeter.com at the end of the month after quality checks; the presentation indicated the audit team was incorporating the results of 88 meters still being finalized.

What happens next: town staff said they will validate the auditor’s findings at the account level, contact affected customers, and pursue corrective steps — including refunds or bill adjustments where appropriate — and implement procedural changes such as recurring multiplier checks and improved system flags to identify misclassified billing codes or unusual usage sooner. The town also reiterated it will continue meter replacement and asset‑management efforts to reduce age‑related accuracy issues.

Why it matters: the audit checks the accuracy and fairness of utility billing for roughly 93,000 accounts in Gilbert. While the report stopped short of finding a systemic failure, the town’s plan to review and remediate affected accounts aims to address residents’ billing concerns and restore confidence.

Quotes

“We found some anomalies that affected just under 3% of accounts. The good news is 97.1% of all accounts were recording usage and billing accurately during the audit period,” Tyler Kay, Kimley Horn project manager, said during the presentation.

“The audit confirmed there are no systemic issues with our water meter system. That matters and it should help restore confidence in the overall system,” Hawin New Hansen, Gilbert finance director, said. Ending

Kimley Horn promised a final, detailed report and the town said it would follow up publicly with account‑level outcomes and an implementation plan for the recommended process improvements.