What should an Arizona public water system do after missing a required sample?

Identify the required sample, monitoring period and what was actually collected or reported. Preserve the schedule, laboratory records and submission evidence. Ask the responsible operator and drinking-water authority whether the event is missed monitoring, late reporting or another violation; those are not interchangeable descriptions.

Use the AZSDWIS record-lookup guide to identify the relevant public system and interpret listed periods or violation types. A displayed record does not replace the operator’s actual event file, authority confirmation or notice duties.

ADEQ's Public Notification Rule page explicitly includes failure to test among events requiring public notice. A missing sample does not by itself prove the water contained a harmful contaminant. It also leaves a gap that cannot be described as evidence of safety. Have the authority determine the required response rather than declaring the matter closed when a later result is satisfactory.

A positive-coliform result starts a different sampling and notification task. Keep that response separate from correcting a missed routine requirement.

ADEQ describes three notice tiers: immediate notice within 24 hours for potential immediate health impacts, notice as soon as possible within 30 days for Tier 2 violations, and up to a year for Tier 3 events such as a required sample not taken on time. Do not assign the longest window to every monitoring problem yourself. Confirm the actual tier, deadline and any instructions from ADEQ or the delegated county authority.

Use the applicable current template and required language. Describe the event and affected period accurately, explain corrective work and include the required customer instructions and contact details. Do not add an unsupported assurance that the system was safe throughout the unmonitored period.

Distinguish this compliance notice from an annual consumer confidence report. Some Tier 3 notices may be distributed with an annual report, but that does not change a different notice's deadline or delivery requirements.

Confirm the methods required for the system type and affected audience. ADEQ's Certificate of Distribution distinguishes community and noncommunity delivery arrangements. A notice posted where only a small portion of the audience can see it may not satisfy the applicable distribution requirements.

ADEQ requires the certificate within 10 days of sharing the public notice. Retain the final notice, dates, delivery methods and the submitted certification with the monitoring record. Assign the next sampling and reporting tasks to prevent another missed period. The operator agreement should make responsibility clear without treating a contract as proof that work occurred.

Where the system uses ADEQ’s baseline contractor, also check the Monitoring Assistance Program owner-duties guide. Clarifying covered and excluded samples helps assign the next monitoring tasks; participation does not erase the missed event.

For the longer-term file, use the compliance-record retention guide to distinguish the notice and certification period from analytical results and corrective-action records. Retaining those documents does not replace the immediate delivery and correction steps.