Plumbing emergencies don't happen during business hours — they happen at midnight when the basement floods, on Sunday morning when the kitchen sink backs up, and on Christmas Eve when the water heater quits. By the time the phone rings, the homeowner is already panicking. The plumber who picks up first wins the job; everyone else is a name on a Google search.
Trade journals like Plumbing & Mechanical consistently report that emergency calls drive 25-35% of revenue at most service plumbers — and the conversion rate on those calls collapses if pickup takes longer than three rings. Voicemail loses roughly half of after-hours emergency callers.
Most shops staff a dispatcher during the day and let calls roll to voicemail at night and weekends. A few hire a 24/7 answering service for $500-800 a month. Those services take a message — they don't book, they don't qualify, and they don't transfer to your on-call tech. The homeowner is told 'we'll have someone call you back' and starts dialing the next plumber.
OnCall picks up at 2am the same way it picks up at 2pm. It walks the caller through emergency triage (is the water shut off, where is it leaking, how bad), captures the address and a callback, and either books your first morning slot or — if you've configured a 24/7 transfer — connects them live to your on-call tech in under 60 seconds. See pricing — typical pilots run $80-150 a month in usage, less than two hours of a single after-hours call.