How long should you flush taps after a holiday?
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Key points
- After a holiday, every outlet has stagnated, so flush the whole system, not just the taps you rarely use.
- Run each tap until the temperature stabilises — hot to at least 50°C, cold below 20°C — rather than for a guessed number of minutes.
- Work from the outlet nearest the incoming supply outward, so fresh water is drawn progressively through the pipework.
- Treat showers separately: run them gently, head off where practical, before first use, because the first minute of spray is the highest-risk moment.
- A short absence in a well-run home usually needs flushing only; longer closures and higher-risk premises may need disinfection or sampling, set by the risk assessment.
Flush the taps after a holiday by running every outlet until the water reaches its proper temperature — hot rising to at least 50°C, cold dropping below 20°C — which for most homes means a few minutes per tap. There is no honest single number of minutes, because the right duration is however long it takes fresh water from the mains to travel the full length of the pipe feeding that tap, and that varies from outlet to outlet.
The reason for flushing at all is stagnation. While the house stood empty, the water in every branch sat still, and still water that drifts into the 20°C to 45°C range is where legionella establishes and grows. A fortnight of stagnation in a healthy system is a modest risk, but the fix is cheap: turn the water over before anyone uses it, and the condition the bacteria depend on is gone.
Flush to temperature, not to the clock
Guessing a time is the common mistake. Two minutes might clear a short branch from a combi boiler to a kitchen tap, and leave a loft-fed bathroom tap on the far side of the house still running its standing water. Temperature is the honest measure because it tells you the turnover has actually happened: when the hot tap is properly hot and the cold tap is properly cold, the water at that outlet is coming from the supply, not from the pipe. Our guide on how long to run taps when flushing covers the principle in more depth, and the temperature checker lets you record what each outlet actually reaches.
Work through the system in order
Start at the outlet nearest to where the water enters the property — usually the kitchen tap on a mains-fed system — and work outward to the most distant outlets. This draws fresh water progressively along the pipework, so each branch you flush is fed by water that has itself been refreshed. Do not forget the ones people skip: the outside tap, the utility room sink, the en suite in the spare room, and the bath tap that everyone showers past. Showers deserve their own care — see the section below.
Give the shower its own routine
A shower is the outlet that turns standing water into a fine, breathable spray, which is the route by which legionella reaches the lungs. After weeks away, do not step straight under it. Remove the shower head where practical, or run the water gently so it streams rather than mists, until it reaches full hot temperature. Then clean and descale the head before refitting it — scale is where the bacteria shelter — following the method in our guide to cleaning shower heads. Our page on legionella in shower heads explains why this one outlet carries most of the risk.
Free legionella risk assessment template
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How long an absence changes the answer
The length of time the property stood empty sets the scale of the response. A week or two in a normally occupied, well-maintained home: flush everything to temperature and carry on. A month or more, a property that has been void between tenants, or a holiday let between bookings: the same flush, but now it should be a documented routine rather than an informal habit, because someone other than you may be exposed. Longer closures, buildings with stored water tanks, and premises with vulnerable occupants move the response from flushing toward the recommissioning steps in making a water system safe after it has stood unused, which may include disinfection or sampling.
The flush is finished when the temperature says so, not the clock. Hot at 50°C and cold below 20°C at the tap is the proof that the standing water is gone.
If you let the property out, write it down
For a homeowner, the post-holiday flush is a sensible habit. For a landlord or a holiday-let operator, it is a control measure, and a control measure only counts if it is recorded. Log the date, the outlets flushed, and the temperatures reached in a log book, and name the flushing routine in the written scheme that comes out of your flushing regime for little-used outlets. The record is what demonstrates, to an insurer or an inspector, that the control actually happened between one booking and the next.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Frequently asked questions
How long should you run the taps after being away on holiday?
Run each outlet until the temperature at the tap stabilises, not for a fixed number of minutes. On a hot tap that means running it until it reaches at least 50°C, and on a cold tap until it drops below 20°C. For most homes that works out at a few minutes per outlet, but a tap on a long pipe run takes longer than one near the cylinder or boiler, which is why the temperature, not the clock, is the measure that tells you the standing water has been replaced.
Is it safe to use the shower straight after a holiday?
Run it first rather than stepping straight in. A shower that has stood for a fortnight can release a concentrated aerosol in its first minute, so the safer routine is to remove the shower head or run the water gently into the drain until it reaches full hot temperature, clean and refit the head, then use it normally. The longer the property has stood empty, the more this matters.
Do you need to disinfect the system after a two-week holiday?
For a typical occupied home with a well-maintained system, a thorough flush of every outlet after a couple of weeks away is usually enough. Disinfection or sampling comes into play after longer closures, in higher-risk premises such as healthcare or care settings, or where the risk assessment identifies a system that cannot hold temperature. The judgement sits with the risk assessment, not a blanket rule.
Should you flush every tap or just the ones you use least?
After a holiday, every outlet has been standing, so flush the whole system, not just the little-used ones. Start at the outlet nearest the incoming supply and work outward to the farthest, so fresh mains water is drawn progressively through the pipework rather than being pulled past branches you have not yet flushed.
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