You’ve done the job. The customer was happy. You left the site tidy, the boiler is running, the bathroom looks great. You sent the invoice the same evening. And then you waited.
A week goes by. Then two. You send a polite follow-up. Another week passes. You chase again. By the time the money finally lands in your account — if it does at all — you’ve spent more time and energy chasing it than the job probably deserved.
Sound familiar? You’re not alone. Late payment is one of the most damaging and least talked-about problems in the plumbing and heating industry. It doesn’t show up on your profit and loss. It doesn’t appear on any report. But it quietly chips away at your cashflow, your stress levels, and your ability to run the business properly — every single week.
The Scale of the Problem
UK small businesses are collectively owed billions in late payments at any given time. In the construction and trades sector, the problem is worse than almost any other industry. Research consistently shows that the average small trades business waits significantly longer than agreed payment terms to receive money owed — and many invoices are never paid at all.
For a plumbing business turning over £300,000 a year, even a modest percentage of invoices paid late or not at all represents a serious amount of money. And the real cost goes beyond the invoice value itself. When you’re chasing payments, you’re not pricing new jobs, visiting new customers, or managing the business. Your time has a value too.
Why It Happens
Late payment in the trades isn’t always deliberate. Some customers genuinely forget. Some are disorganised. Some are waiting for their own money to come in before paying yours. And some — particularly in commercial work — have payment processes that simply don’t move quickly.
But here’s the thing: however it happens, the impact on your business is the same. A job that looked profitable on paper becomes a cashflow problem in practice. You’ve bought the materials. You’ve paid your team members. The job is done and dusted. But the money isn’t there yet.
If this happens across multiple jobs at the same time — which it often does — you can find yourself in a position where your bank account tells a very different story to your invoicing software. You’re profitable on paper. You’re broke in practice. That gap is a late payment problem.
The Deposit Habit
The single most effective thing most plumbing businesses can do to reduce their late payment exposure is to start taking deposits. Not for every small job — a quick fix or a service call doesn’t need one. But for anything significant: a boiler installation, a bathroom refit, a new heating system, a large commercial maintenance contract.
A deposit does two things. It improves your cashflow by getting money in before the work starts. And it filters out the customers who were never going to pay you properly in the first place. A customer who refuses to pay a reasonable deposit on a £3,000 bathroom job is showing you something important. Listen to it.
Most customers in the plumbing and heating industry are completely comfortable paying a deposit when it’s presented professionally and explained clearly. The awkwardness around asking for one is almost always in the business owner’s head, not the customer’s.
Invoice at Completion, Not at the End of the Month
Many plumbing businesses fall into the habit of batching their invoices — sending everything out at the end of the week or the end of the month. It feels efficient. It is actually one of the most expensive habits in the industry.
Every day between completing a job and sending the invoice is a day you’ve added to how long it takes to get paid. If your payment terms are 14 days and you wait a week to send the invoice, you’ve effectively given yourself 21-day terms without agreeing to them.
Invoice the moment the job is done. Not tomorrow. Not on Friday. That evening, from the van, on your phone if necessary. The faster the invoice goes out, the faster the clock starts.
Your Payment Terms Are Not Suggestions
Here’s something that catches a lot of plumbing business owners out. Your payment terms need to be agreed before the job starts, not buried in small print at the bottom of an invoice sent after it’s finished.
When you quote a job, your terms should be clear: deposit required, balance due on completion, or payment within seven days — whatever you decide. Get confirmation. And when you send the invoice, reference those terms explicitly.
When an invoice is overdue, follow up immediately. Not after two weeks. Not after a month. The moment a payment term is missed, contact the customer. A polite but direct message — “I notice the invoice for [job] is now overdue, please can you confirm when payment will be made” — is not rude. It is professional. Customers who pay on time expect it. Customers who are slow to pay need it.
Staged Payments on Larger Jobs
For anything running over more than a few days, consider staged payments rather than a single invoice at the end. A heating installation that runs across a week might reasonably have a deposit upfront, a midpoint payment when first fix is complete, and a final balance on completion.
This protects you in two ways. It keeps your cashflow positive throughout the job rather than leaving you out of pocket until the end. And it means that if something goes wrong — a dispute, a difficult customer, an unexpected complication — you’re not chasing the full amount from scratch.
Know Your Numbers
The businesses that handle late payment best are the ones that know their cashflow position at all times. Not just their bank balance — that tells you what happened last week. But what’s outstanding, what’s due in the next seven days, and what’s already overdue.
A simple aged debtors list — even a basic spreadsheet — gives you a clear picture of who owes you what and for how long. When you can see that at a glance, you can prioritise your chasing, spot patterns in which customers are consistently slow, and make better decisions about who you take on as a customer in the future.
Late payment is a problem you can manage. But you have to be deliberate about it. And that starts with knowing exactly where you stand.
If you want to understand how to price your jobs correctly, set up payment terms that protect your cashflow, and build the financial foundations of a properly profitable plumbing or heating business, The Quote Handbook walks you through it step by step. Grab your copy here: https://amzn.to/3WzrTkJ
Stop letting good work go unpaid. Start running your money as professionally as you run your jobs.