The Case for On-Site Payment
Collecting payment on site — before you leave the customer's property — eliminates the most common cause of late payment: the invoice sitting unread in an inbox while the customer's attention moves on. When payment happens on site, it happens in the moment when the customer is most satisfied with your work and most motivated to complete the transaction.
On-site payment also removes the friction of "I'll transfer it later" promises that frequently become "I'll sort it this weekend" and then "I'll do it next week." Each delay makes payment less likely and follow-up more awkward.
For domestic plumbing work, on-site payment should be your standard expectation. You've completed the work; payment is due. Framing this as normal from the start of the relationship prevents any awkwardness.
Payment Tools That Work on Site
Card readers (contactless and chip+PIN)
A Bluetooth card reader connected to your phone is the simplest way to accept card payment on site. The main UK options:
- SumUp Air: £39 device, 1.69% transaction fee. No monthly fee. Good for plumbers with occasional on-site card payments.
- Square Reader: Free or £19 device, 1.75% transaction fee. Includes a good free invoicing app.
- Zettle by PayPal: £19–£29 device, 1.75% transaction fee. Good app and inventory management.
- SumUp Solo: £79 device with built-in SIM — works without a phone, ideal for areas with poor mobile signal.
On a £500 job, a 1.75% card fee costs £8.75. That's less than the cost of sending one reminder email, chasing by phone, or waiting 30 days for your money. Accept card payments without hesitation.
Payment links
Generate a payment link from your invoicing app (Stripe, GoCardless, Square) and text or email it to the customer as you're packing up. They tap the link on their phone and pay by card or bank transfer instantly. Many customers prefer this to a physical card reader.
Bank transfer on the spot
Ask the customer to open their banking app and transfer the amount while you're still there. Give them your account number and sort code verbally or on a printed card. This works well with customers who prefer not to use card payments.
The Script: Asking for Payment Without Awkwardness
The way you ask for payment shapes how customers respond. The key is to frame on-site payment as normal and expected — not as a demand or an afterthought.
As you're finishing up, say something like:
"That's all done — I'll just get your invoice raised while I'm here. Are you happy to pay by card, or would you prefer a bank transfer?"
This phrasing:
- Assumes payment will happen now (not "if you'd like to pay now")
- Gives the customer a choice about method (not whether to pay)
- Feels professional and natural rather than demanding
If the customer says they'd prefer to pay later: "No problem — I'll send the invoice now, and it's due within 7 days. I can send a payment link if that's easier than a bank transfer."
Then send the invoice immediately (from your phone), and set an automated reminder for day 8 if it hasn't been paid.
Invoicing From Your Phone on Site
Modern job management apps let you generate and send a complete, professional invoice from your phone in under 2 minutes. If you're still writing invoices on paper or generating them on a computer at home later, this is the process change that will most dramatically improve your cash flow.
Apps with strong mobile invoicing:
- Tradify: Generate a branded PDF invoice from completed job details, send by email with a payment link. From £15/month.
- Square Invoices: Create and send invoices from the Square app with card payment links. Free for basic invoicing.
- Invoice Ninja: Free invoicing app with payment integration. Good for sole traders who want a standalone invoicing tool without job management.
Set up invoice templates in advance — your company name, logo, standard terms, bank details, and VAT number (if applicable). When a job is done, you just add the job description, labour hours, and materials. Takes 2–3 minutes. The customer gets a professional invoice instantly.
Building an On-Site Payment Habit
The first few times you ask for on-site payment may feel uncomfortable if you're not used to it. After a few weeks, it becomes automatic — part of the job completion sequence alongside packing your tools and checking your work.
Make it part of your closing routine: tools packed, site cleaned, invoice generated, payment request made. Every time. Without exception. The rare customer who can't or won't pay on site gets a 7-day terms invoice sent immediately and an automated reminder if it's not paid on day 8.
Track your on-site payment rate. If 80%+ of domestic customers pay on site or within 24 hours of job completion, your cash flow will transform within a few months. The days of waiting 30, 60, or 90 days for money you've already earned will largely disappear.