Start with the reason this seat exists
Is the opening for residential service and emergency calls, commercial rough-in and inspection work or new construction, remodels and fixture installations? Those needs produce different screening standards. Decide which tasks a new hire must perform without additional training and which the employer can teach. Use that distinction before you read the first resume.
Build two lists, not one impossible list
List verified hard requirements such as a jurisdiction-specific license or a safety qualification required for the exact assignment. Then list trainable preferences. Distinguish service plumbing, commercial construction, drain work and gas-related scope. For a genuinely junior opening, the ability to follow instruction may matter more than familiarity with every tool brand.
Use evidence-based questions
Ask for a real example involving recurring under-sink leak after repair, including the candidate’s personal contribution and the person who verified the result. A second prompt might be “What would you rule out before cutting into finished work to address a repeat leak?” Listen for their process, honest scope and willingness to escalate when conditions are unsafe.
Avoid false negatives from jargon
One shop may call code references, approved test equipment, pipe tools and jobsite protection materials by a different name than another shop. Ask the person to describe what they used and why. Someone with relevant experience in a neighboring environment may be able to transition with structured training; do not confuse an exact keyword match with proven competence.
Make the decision reproducible
Use a scorecard based on the specific work, not a vague “culture fit” impression. Record which essential criteria were met, what needs follow-up and what training the company can provide. Share accurate scheduling and pay information early. Treat all applicants consistently and comply with applicable employment rules.