A 2-wave sequence built around getting ahead of the freeze: a pre-season inspection now, before a holiday emergency. Bring a spreadsheet, no CRM required.
Start FreeHomeowners don't think about pipes until something goes wrong, and when it does, they call whichever plumber answers the phone. The contractor who prevents the emergency call wins the customer for life. The one who only takes emergency calls is competing on price every time.
2 waves over 2 weeks, deployed late September through November (winterization) or February through March (spring checks). Below is exactly what mails when.
Headline: "Winterize Your Pipes" · Offer: Seasonal pipe inspection + water heater check at pre-season rate.
Direct, professional, and specific about what's included: water heater, exposed pipes, shut-off valves, outdoor spigots. List "licensed and insured master plumbers" prominently. This is a credibility-driven decision. Bold pricing, big phone number. Plumbing customers prefer to call rather than book online. The Wave 1 call lands about 5 business days after delivery by default: "We're scheduling pipe winterization checks now at a pre-season rate. A burst pipe on a cold weekend is a mess nobody wants."
Headline: "Don't Wait For The Emergency" · Offer: Pipe inspection + water heater flush, ends [date].
14 days after Wave 1, only to non-responders. The hook is the deadline: "Pre-season pricing ends [date], book before the cold snaps." A pre-season inspection can help you avoid a 2 AM emergency. Free water heater flush as a bonus to push the deadline conversion. Postcard only, no call. The deadline does the work. After Wave 2, the contact rests for 90 days, which lets you cycle into spring or summer maintenance campaigns without overlap.
Both waves, call timing, and copy direction are pre-configured. You set the price, the inspection items, and your branding.
From ServiceTitan, Housecall Pro, FieldEdge, or Service Fusion: export past customers. Or layer in purchased lists targeting single-family homes 15+ years old (likely candidates for aging plumbing).
Wave 1 mails within 1–2 business days. Your call queue auto-populates about 5 business days after delivery (adjustable), paced by your calling settings so the office isn't overwhelmed.
Pre-loaded scripts. Office enters bookings into your dispatch software and logs the outcome in PostKnock; a customer whose call you log as qualified drops out of Wave 2 once you log it.
A typical residential plumbing contractor mails to 500–1,500 past customers for the fall winterization push. Here's the math on a 1,000-home run:
7:1 ROI on Wave 1 alone, before counting upsell and the steady stream of replacement work that flows from inspection findings.
Run your own numbers in the ROI calculator.
Free to explore. You only pay when you're ready to send. 30-day money-back guarantee on your first annual plan.
Single-wave postcard campaigns · Unlimited contacts · From $1.04/piece
Everything in Free + calls, sequencing · From $0.91/piece
Per-piece pricing includes printing + USPS First-Class postage. No hidden fees.
Four design styles, all themed for your plumbing business and ready to customize. Same offer, same call follow-up, just pick the look that fits your brand.
Bold
Photo
Minimal
Gradient
Front Detail
Back (Address Side)
PostKnock seasonal campaigns also work for
Seasonal maintenance is the highest-ROI plumbing play, but PostKnock also runs water heater age-based reminders and win-back sequences for lapsed past customers.
See all plumbing campaigns →Late September through November in cold-weather markets. The pre-season window before homeowners feel any urgency. Mail too late (after Thanksgiving) and you're competing with the holidays for mailbox attention. In southern markets where freeze risk is lower but storms still happen, run a generic "seasonal pipe check" angle in October instead. PostKnock's Plumbing Seasonal Maintenance playbook has a Sep–Nov deploy window flagged in the campaign builder.
$99 is the conversion sweet spot for a residential pipe + water heater inspection. A small, fixed price is easy to say yes to when the alternative is an emergency call. Inspections are loss-leaders that pay back through repair, water heater replacement, and the customer-retention effect. Price aggressively to fill the calendar and use Wave 2 to land the deadline.
Past customers first: warm list, response rates 5–9%. After your house list, layer in purchased lists targeting single-family homes 15–30 years old (aging plumbing, water heater near end-of-life, real maintenance need). Cold purchased lists convert at 1–2%, profitable on a $99 inspection that creates a customer for every future plumbing emergency.
PostKnock doesn't integrate with your dispatch software. The call queue and pre-loaded scripts live inside PostKnock, and your staff log each call outcome there. When the office books an inspection, they enter it into ServiceTitan, Housecall Pro, FieldEdge, or Service Fusion. A customer whose call you log as qualified drops out of the sequence once you log it, so they don't get Wave 2. To get customers in, export a CSV or Excel file from your software and import it.
Yes: the Plumbing Seasonal Maintenance playbook flips between fall winterization and spring inspection (post-thaw pipe damage, outdoor spigot checks, water heater flushes) by toggling the season in the campaign config. Deploy late September for fall, late February for spring. Same customer list, 90-day rest cycle between seasonal campaigns.
Stop waiting for the burst-pipe phone call. Fill your fall calendar with $99 inspections that help you get ahead of the emergency.
Start Free1 ANA (Association of National Advertisers), Response Rate Report 2023, published February 2024.