June is one of the best months of the year for plumbing and heating business owners. The diary is full. Bigger installation jobs are flowing in. Turnover is up. On paper, business looks great.
So why do so many plumbing business owners reach August or September and find the bank account doesn’t reflect all that work?
The answer isn’t that they haven’t been working hard. It isn’t that business has been bad. It’s almost always a cashflow timing problem — and it’s one of the most predictable financial traps in the trade.
Let me walk you through what’s happening and, more importantly, what you can do about it.
The Problem With Bigger Summer Jobs
Summer tends to bring a different type of work. Bathroom installations. Full heating system replacements. Heat pump installs. Larger, more complex jobs that take longer and cost more to deliver.
On the surface, this feels like a good thing. And it is — if the pricing is right and the cashflow is managed properly. But bigger jobs come with a financial dynamic that catches a lot of business owners off guard.
Here’s what typically happens. You quote a large installation job. Materials are ordered — and those invoices land within 30 days. Your team members are on site for a week or two. The job finishes in late July. You invoice on completion. Payment terms are 30 days. The money arrives in September.
In the meantime, material costs have gone out in June. Labour costs every week. Fuel, insurance, tools — all running in the background. Your business is carrying the financial weight of that job for two months before you see a penny back.
If you’ve got several of these running at once, the cashflow pressure builds quickly. Turnover looks healthy. But cash is tight.
This Is Different From Profit
It’s worth being clear about something here, because this is a distinction that trips up a lot of business owners.
Cashflow and profit are not the same thing.
You could have a genuinely profitable summer — jobs priced well, good margins — and still struggle with cash because of the timing gap between when you spend and when you get paid. This is one of the reasons businesses that appear to be doing well can suddenly find themselves in difficulty.
Think of it like this. Imagine you’re a farmer. You plant seeds in April, tend them through the summer, and harvest in October. All the costs go out in the first half of the year. The income arrives at the end. You might be running a perfectly profitable farm — but if you run out of cash before harvest, it doesn’t matter how good the crop is.
Plumbing businesses run a version of this cycle every single summer. The question is whether you’ve planned for it.
The Practical Fixes That Make the Biggest Difference
There are three things that change this picture significantly, and none of them require an accountant or complicated software.
First: always take a deposit on larger jobs. This is the single most effective cashflow tool available to a small plumbing business. A 25 to 30 per cent deposit on a large installation — collected before work starts — covers a meaningful chunk of your material costs upfront. Most customers expect it from a professional business. It also filters out time-wasters. If someone won’t pay a reasonable deposit, that tells you something before you’ve spent anything on their job.
Second: invoice as early as the contract allows. On multi-week jobs, consider milestone invoicing — a payment when materials are delivered, a further payment when the job is half complete, and a final balance on completion. This spreads the income across the job rather than waiting until the very end. If your customers are used to paying everything at the end, this might require a conversation. Have it. It’s worth it.
Third: know your cashflow position at all times. Not your profit — your cash. What’s in the bank right now, what’s going out in the next thirty days, and what’s coming in. A simple weekly check of these three numbers will alert you to a squeeze before it becomes a crisis. You can then make decisions — chase an outstanding invoice, defer a non-urgent purchase, call a customer to check on payment — before you’re under pressure.
What Summer Often Hides
There’s another cashflow issue that summer specifically creates, and it’s easy to miss.
VAT. If you’re VAT registered and your turnover spikes in the summer, your VAT bill will be larger than expected when it falls due. Money that felt like income has a liability attached to it that doesn’t show up for another three months. If you haven’t been setting it aside as you go, that bill can land at exactly the wrong moment.
The fix is simple but requires discipline: every time an invoice goes out, set aside the VAT portion in a separate account. Treat it as money that isn’t yours from the moment it arrives. When the bill comes, you’re ready for it.
Build the Financial Habit Now
Summer is one of the best opportunities you’ll have all year to build strong financial habits — because the volume of transactions gives you real data to work with. Track what comes in. Track what goes out. Note the timing gaps. Start taking deposits on larger jobs if you don’t already.
By the time autumn arrives, you’ll have a much clearer picture of how your business actually performs financially — not just what it turns over, but what it retains, and when.
This is the kind of financial thinking I cover in The Quote Handbook — understanding your numbers, pricing for real profit, and managing the money side of your business with confidence rather than guesswork.
Once you’re ready to learn how to actually implement this in your business, the full step-by-step process is covered in my books.
Get your copy of The Quote Handbook here: https://amzn.to/3WzrTkJ