How do I collect an unpaid invoice from a plumbing customer?
How to collect an unpaid plumbing invoice — residential and commercial
Short answer
Plumbing invoice collection works best when you collect at the door or send a payment link within 24 hours of the job. For invoices already past due, a direct call that references the specific job — not a generic reminder — recovers most residential balances within the first 14 days. For commercial plumbing work, verify the correct accounts payable contact and check that your invoice includes any required purchase order number.
Plumbing service invoices share the same collection dynamic as HVAC: once the pipe is fixed or the drain is clear, the problem is gone and the urgency to pay follows. Payment collected at job completion — card on file, tap-to-pay, or a payment link sent while the tech is still on site — has the highest closure rate. If the customer defers, the 24–72 hour window after the call is when the job is still fresh and a follow-up feels natural rather than aggressive.
For emergency plumbing calls — burst pipes, sewage backup, flooding — customers are often willing to give card authorization over the phone or on arrival just to get someone there. Requiring a deposit or card authorization before dispatch is standard practice for emergency calls and dramatically reduces collection problems downstream. Include this policy in your booking confirmation so customers aren't surprised.
Commercial plumbing — property management, restaurants, schools, hospitals — typically runs on net-30 invoicing with a formal AP process. The main collection failure here is invoicing the wrong contact (the facility manager who called you versus the AP department) or submitting an invoice without a purchase order number. Confirm these details before starting any commercial job. A 2-minute verification at the start saves a 30-day delay at billing.
For new construction plumbing, you are typically a subcontractor on a GC-managed project. Preliminary notice rules apply — file the notice within 20 days of starting work in most states. Retainage holdbacks are common (5–10% held until project completion). Your contract should define the completion trigger and the retainage release timeline. If the GC delays retainage release past the contractual deadline, a demand letter citing the contract terms usually prompts action.
Lien rights are plumbers' most underused collection tool. A mechanics lien on a residential property — even for a $400 service call — clouds the title and must be resolved before the property can be sold or refinanced. The threat alone resolves many disputes. Filing fees are typically under $100. Syntharra handles the early phone follow-up on residential and commercial plumbing invoices, which resolves most balances before liens become necessary.