For Residential Service Plumbers ·
What you'll accomplish
By the end of this guide, you'll have a custom AI assistant in ChatGPT that already knows your pricing, your services, your communication style, and how you run your business — so every conversation with it starts from a shared understanding instead of from scratch. Instead of explaining your labor rate every time you need an estimate, just describe the job.
What you'll need
Go to chat.openai.com. If you have a free account, click Upgrade to Plus in the left sidebar and follow the payment steps. You need Plus for the Custom GPT feature.
What you should see: After upgrading, your sidebar shows a "GPT-4o" option at the top and new features including "Explore GPTs."
In ChatGPT, click your account icon (top right or bottom left) → My GPTs → Create a GPT. This opens the GPT builder.
What you should see: A two-panel screen — "Create" on the left (where you configure your GPT), "Preview" on the right (where you test it).
In the "Create" panel, click Configure (tab at the top). Scroll to the Instructions box. This is where you tell the AI who it is and how to behave. Paste and customize this:
You are a plumbing business assistant for [Your Name/Shop Name], a residential plumbing contractor in [City, State].
My business details:
- Labor rate: $[X]/hour
- Service area: [City and surrounding areas]
- Typical jobs: drain clearing, water heater replacement, faucet/toilet repair, leak repair, repipes
- I work solo / I have [X] technicians
My pricing approach:
[Paste your flat-rate guide or write a summary like: "I use flat-rate pricing. Water heater replacement: $[amount]. Drain clearing: $[amount]." etc.]
Your job is to:
1. Help me write professional estimates — when I describe a job, output a formatted customer estimate
2. Help me write professional customer texts and emails
3. Help me draft Google review responses (positive and negative)
4. Answer questions about plumbing code and best practices
5. Help me troubleshoot parts identification when I describe what I'm looking at
Always write in a friendly, professional tone. Keep customer communications brief and clear. When writing estimates, always include a scope description, itemized parts and labor, total, and one sentence explaining why the work is needed.
What you should see: The instructions saved in the box. The preview panel on the right will update.
At the top of the Configure panel, name it something memorable like "Plumbing Assistant" or "[Your Name]'s Shop Bot." For Description, write: "My personal business assistant for estimates, customer emails, and job support."
Under Knowledge, click Upload files. Upload any of these:
ChatGPT can read these and reference them when you ask for estimates.
Troubleshooting: If uploads fail, the Instructions box above is enough to get started — you can add files later.
Click Save in the top right. Choose Only Me for visibility. Now click View GPT to open it.
In the chat, type: "Write an estimate for replacing a toilet. Customer has a standard toilet, parts cost approximately $95, labor will be about 1.5 hours."
What you should see: A formatted estimate using your labor rate, with your pricing structure.
Quick estimate: "Write a customer estimate for [describe job]. Parts cost: $[X]. Labor: [hours] hours at my rate."
Decline a sketchy job politely: "Write a professional text declining a job. Reason: [the work is outside my license/too far away/timing doesn't work]. Keep it friendly and leave the door open for future work."
Explain a diagnosis: "I told a customer they need [repair]. They seem skeptical about the cost. Write a short plain-English explanation of why this fix is necessary and what happens if we don't do it."
End-of-job text: "Write a short text to send after completing [job type]. Customer was [happy/had questions about]. Thank them and mention we're here if they need anything."
Training reminder to helper: "Write a quick job completion checklist for a toilet replacement that I can text to my apprentice before his first solo toilet job."