Build the microbiological sample-siting plan around the system’s actual sources and distribution, with identified routine and repeat taps and an accompanying map. Use the agency template for the population served, explain representative locations, and obtain required approval for alternatives. Keep the plan current; a convenient faucet is not automatically an authorized sample site.
Which system information should the plan describe?
ADEQ publishes different Microbiological Sample Siting Plan (MSSP) templates for systems serving 1,000 or fewer people and 1,001 or more. Select the applicable form with the drinking-water authority and responsible operator. The templates ask for the system’s identification, classification, population, source types, purchased water and treatment information.
Start with the actual regulated system. A privately owned business supply can be a public water system. A household testing checklist does not replace that system’s monitoring plan. Confirm whether ADEQ or a delegated authority administers the program and which current template it wants.
How are routine and repeat locations documented?
The templates identify routine sampling taps and corresponding upstream and downstream repeat locations using specific location identifiers. Record the actual tap location and explain how the selected locations represent water quality in the distribution system. Attach additional sites where needed rather than leaving an unexplained gap in the form.
A kitchen faucet chosen because it is easy to reach is not automatically a suitable compliance site. Have the operator evaluate sampling access and the distribution layout. ADEQ’s templates expressly require written regulatory approval for identified alternate repeat locations before implementation. A substituted location should therefore be resolved through the plan process, not quietly used when the regular tap is inconvenient.
What source and map details belong in the file?
List the applicable groundwater sources and source-sampling locations. The templates distinguish systems subject to triggered groundwater-source monitoring from specified treatment situations; the owner should not select an exemption simply because some treatment equipment is installed.
Provide a distribution or plumbing map identifying the applicable routine, repeat and groundwater-rule sites. Make the location names consistent across the map, laboratory records and plan. Explain how routine, repeat and relevant triggered-source sampling will be performed under the applicable requirements. The plan establishes locations and procedures; it does not let the owner choose a less frequent monitoring schedule without required approval.
If the supplier relies on an approved source blend for contaminant-limit compliance, the blending-plan and monitoring guide explains its separate downstream verification. A microbiological siting plan does not automatically establish that program’s locations or schedule.
When should the owner review the plan?
Keep the plan available, retained and updated as the template directs, and provide it to the authority on request. Have the operator review changes in sources, distribution, service arrangements or access that could make a listed site inaccurate. Confirm revisions and agency review before relying on a changed location.
A coliform-positive result creates a time-sensitive response that depends on this plan; writing a new plan does not erase the result or replace required repeat sampling. The sanitary-survey file should likewise contain the current plan and map rather than an obsolete copy.
If the event triggers an assessment for a system serving 1,000 people or fewer, use the small-system Level 1 or Level 2 guide for that separate submission and corrective-work process.