Service Call Dispatch & Diagnosis: the full procedure

Get the plumber to the right address with the right information and a confirmed, documented diagnosis before any repair is priced.

• Applies to: Plumber or apprentice on a service call.
• Frequency: Every service call.
• Scope: Covers receiving the dispatch, arriving, greeting the customer, and diagnosing the reported problem. Does NOT cover code rulings or any gas/hazardous diagnosis, which defer to a licensed plumber, the plumbing/gas code, and the business safety plan.

What you need

• Dispatch ticket / job app on phone or tablet
• Customer history notes
• Basic hand tools and flashlight
• Moisture meter or test gauge
• Camera (phone) for documentation
• Diagnosis checklist form

The procedure, step by step

1. Review the dispatch before you roll — Read the ticket for address, contact, reported symptom, and any access notes. Confirm the appointment window by text or call so the customer expects you.
2. Arrive on time and announce yourself — Park without blocking the customer, knock, and introduce yourself by name and company. Confirm you are at the right unit and the right problem.
3. Ask the customer to walk you to the issue — Have them describe what happened, when it started, and what they have already tried. Listen for clues the ticket did not capture.
4. Inspect the reported problem firsthand — Observe the fixture, line, or appliance in the failure condition if safe to do so. Note water on, off, or intermittent behavior.
5. Test to confirm the root cause — Run the fixture, check pressure, or trace the line to verify the actual fault rather than the obvious symptom. Distinguish cause from effect before quoting.
6. Flag anything code, gas, or hazard related — If the issue involves gas, venting, backflow, or possible code violations, stop and route to a licensed plumber per the business safety plan. Do not diagnose or price hazardous work on the spot.
7. Photograph and document the findings — Capture before photos and write a plain-language diagnosis on the ticket. This becomes the basis for the quote and the customer’s understanding.
8. Explain what you found to the customer — State the problem, the likely fix, and the next step in terms they understand. Confirm they want a price before you proceed.

Quality check before you finish

• Appointment window was confirmed before arrival
• Customer was greeted by name and company
• Root cause confirmed by test, not assumed from symptom
• Any gas/code/hazard item routed to a licensed plumber
• Before photos taken and attached to ticket
• Plain-language diagnosis written on the ticket
• Customer agreed to receive a price before work began

This is a free, source-anchored standard operating procedure (SOP) you can print and hand to staff. It documents the work sequence for a Plumbing business — not safety or regulatory rulings, which defer to the cited authorities, the applicable code, and your own health-and-safety plan. Open the tool above to print it, toggle ink-saver, or (with a free ToolFluency Business account) edit it to match your own workflow.

Sources

• Plumbing-Heating-Cooling Contractors Association (PHCC) (phccweb.org)
• ServiceTitan Contractor Playbook (Call Center + Field Practices) (servicetitan.com)
• This Old House (plumbing how-to / diagnosis) (thisoldhouse.com)