Going on Holiday? How to Leak-Proof Your Home Before You Leave

There are few worse ways to end a holiday than opening your front door to the smell of damp, a bulging ceiling and water quietly running somewhere it should not be. It happens more often than people think, and it almost always follows the same pattern: a small weakness that was already present under the sink or behind the washing machine finally gives way, and with nobody home to notice, a slow drip becomes a flood over ten or fourteen days.

The frustrating part is that this is one of the most preventable problems in the home. A leak that would have been a five-minute mop-up if you were in the house becomes a four-figure repair simply because nobody was there to turn a tap. This guide walks through a sensible pre-holiday routine that takes most people under an hour: ruling out a leak you already have, shutting off the water supply the right way, checking the parts most likely to fail, and understanding the small print in your home insurance that catches so many people out.

Why coming home to a flood is so avoidable

Water damage is rarely dramatic at the start. The joints, seals and flexible hoses that carry water around your home wear slowly. A flexi-hose under a basin might weep a few millilitres a day for months without anyone noticing, because the small amount evaporates or drains away. The moment the braided sleeve finally fails, though, that same hose can release water at mains pressure, hour after hour, with nobody to hear it.

When you are at home, you catch these things early. You notice the tea towel under the sink is damp, you hear the boiler topping up more often than usual, or you spot a tide mark on the skirting board. When you are away, none of those early warnings reach you. The single most effective thing you can do is remove the water supply from the equation entirely, so that even if something does fail, there is nothing behind it to cause harm.

The consensus you will find across DIY and home-owning communities such as r/DIYUK, r/AskUK and the MoneySavingExpert forums is refreshingly consistent on this point. When people share stories of returning to a flooded kitchen, the replies almost always come back to the same two lessons: turn the water off at the stopcock before a long trip, and check your insurance terms for unoccupied properties. The advice is boring precisely because it works.

Step one: rule out a leak you already have

Before you think about switching anything off, it is worth confirming you are not already leaking. A slow, hidden leak will only get worse while you are away, and catching it now means you leave with genuine peace of mind rather than a nagging doubt.

The simplest home check is the water meter test. Turn off every tap and water-using appliance in the house, take a reading from your meter, wait a couple of hours without using any water, then read it again. If the numbers have moved with nothing running, water is escaping somewhere. Our step-by-step guide on how to read your water meter to check for a leak walks through exactly how to do this and how to interpret the dials.

Also worth a quick look before you pack: the pressure gauge on your combi boiler. If it keeps dropping and you find yourself topping it up, that can point to a leak somewhere on the heating circuit. And trust your senses around the usual suspects, under sinks, around the base of the toilet, behind the washing machine and around radiator valves. A musty smell, a warm patch on the floor near a heating pipe, or paintwork that is lifting are all worth investigating rather than ignoring on your way out the door.

If the meter test suggests something is escaping but you cannot see where, that is exactly the situation where a short, non-invasive leak survey before a long trip earns its keep. We cover how professional detection works later in this article.

Step two: turn off the water at the stopcock

This is the single most important action on the list. If the water is off at the mains, a failed hose or split joint has nothing to feed it. Your internal stopcock, sometimes called a stop tap, is usually found under the kitchen sink, but in London homes it can also live in a downstairs cloakroom, an airing cupboard, under the stairs or near the front door. It is a small valve on the pipe where the mains water enters your home.

To shut it, turn the handle clockwise until it stops. Then open a cold tap at the lowest point in the house, the kitchen is fine, and let it run until it slows to a trickle, which confirms the supply is genuinely off. If you have never located or operated yours, our guide on how to turn off your water stop tap in London explains where to look and what to do if the valve is stiff or seized, which is very common in older properties that have not had the stopcock touched in years.

What if you cannot turn the whole supply off?

There are legitimate reasons to leave the water on. You might have a combi boiler set to a frost-protection cycle, a smart heating system, a water-fed fridge with an ice maker, or a neighbour watering plants. If you need to keep the mains live, the next best thing is to isolate the highest-risk appliances individually.

Most washing machines and dishwashers have their own isolation valves on the supply pipes behind or beneath them, usually a small lever or a screw-slot valve. Turn these a quarter-turn so the lever sits across the pipe, and the appliance is isolated even with the mains on. The same applies to the flexible tails feeding basin and sink taps, which often have isolation valves fitted underneath. Isolating the appliances that fail most often gives you much of the protection of a full shut-off without disabling the whole house.

Step three: check the parts most likely to fail

A few minutes spent looking at the components that cause the most escape-of-water claims is time well spent. You are not carrying out a full plumbing inspection, just a visual once-over of the known weak points.

Flexi-hoses deserve a special mention because they come up again and again in forum threads about unexpected floods. They are cheap, they are hidden, and they have a finite lifespan, often quoted as around five years, though many fail sooner or last longer depending on water quality and pressure. If yours look tired, corroded or you simply cannot remember when they were fitted, replacing them is a small job with a large payoff. As a typical UK trade cost-guide range, having a plumber swap a pair of flexi-hoses tends to fall somewhere in the region of eighty to a hundred and fifty pounds including parts, and it is the kind of job many confident DIYers take on themselves for the cost of the hoses alone.

Step four: drain the appliances that hold water

Washing machines and dishwashers hold water in their pumps and hoses even when switched off. On a long trip it is worth running a short empty cycle to clear them, then switching them off at the socket and, if you can, closing their isolation valves as described above. It is a small habit that removes a standing reservoir of water from behind two of the most flood-prone appliances in the house.

While you are at it, empty and switch off anything that fills or drips, and make sure outside taps are turned off at their internal isolation valve if you have one, particularly heading into winter.

Step five: winter trips need extra thought

Cold-weather holidays add frozen pipes to the list of risks. When water freezes it expands, and a pipe that splits while frozen will happily flood the house the moment it thaws, often days after the cold snap that caused the damage. This is one of the most common causes of serious escape-of-water claims in the UK winter.

The standard advice, echoed consistently across home-owning communities, is not to switch the heating off entirely for a winter absence. Instead, leave it running on a low frost setting, many thermostats have a dedicated frost-protection or holiday mode, or set the thermostat to a modest temperature such as around twelve to fifteen degrees so the property never gets cold enough for pipes to freeze. This matters twice over, because as we will see, leaving an unoccupied home unheated in winter can also give your insurer grounds to reduce or refuse a claim.

If you are draining the system down completely for a long winter absence, that is a more involved job and best discussed with a plumber, but for most fortnight-long trips, a frost setting plus the water off at the stopcock is the pragmatic combination.

Step six: ask a neighbour to check in

Technology helps, but a trusted human is still the best flood alarm. Ask a neighbour, friend or family member to pop in every few days, or at least once, to look, listen and smell for anything amiss. Leave them a key, show them where the stopcock is and how to turn it off, and give them a way to reach you.

Smart leak detectors that sit on the floor by the washing machine or under the sink and send an alert to your phone are increasingly affordable and genuinely useful, but they only help if someone can act on the alert. A sensor that pings your phone while you are on a beach two thousand miles away is only as good as the neighbour who can respond to your call. The two together, a detector plus a keyholder, are a strong combination.

Step seven: know your insurer's unoccupied-property terms

This is the step people most often skip, and the one that turns a bad situation into a genuinely expensive one. Home insurance policies frequently contain conditions about properties left unoccupied, and a leak discovered on your return can be reduced or declined if you did not meet them.

Two conditions come up repeatedly. The first is a time limit: many policies define a property as unoccupied after a set number of consecutive days, commonly around thirty to sixty, after which cover may change or lapse unless you have told your insurer. A two-week holiday is usually well inside this, but longer trips, second homes and properties between tenancies are exactly where people get caught. The second is the seasonal condition: many policies require that during colder months you either keep the heating on at a minimum temperature or drain the water system down. Leave the property cold with the water on over winter, suffer a burst pipe, and the insurer may argue you failed to meet the policy terms.

The exact numbers and wording vary between insurers, so the honest advice is not to rely on any single figure quoted online but to read your own policy documents or ring your provider and ask directly what they require for the length and season of your trip. It is a five-minute phone call that can be the difference between a claim paid and a claim refused.

Your pre-holiday leak-proofing checklist

1. Run the water meter test to confirm you do not already have a slow, hidden leak.
2. Check the boiler pressure gauge and look under sinks, behind appliances and around toilets for damp patches or musty smells.
3. Locate your stopcock and turn the water off at the mains, then run a tap to confirm the supply is truly off.
4. If you must leave the water on, close the isolation valves to the washing machine, dishwasher and high-risk taps.
5. Inspect flexi-hoses and visible joints for rust, bulges, fraying or damp, and replace anything that looks tired.
6. Run a short empty cycle to drain the washing machine and dishwasher, then switch them off at the socket.
7. For winter trips, leave the heating on a frost setting rather than switching it off entirely.
8. Give a neighbour a key, show them the stopcock, and leave them your contact details.
9. Read your insurance policy's unoccupied-property and winter-heating conditions, and call your insurer if anything is unclear.

When a quick leak survey before a long trip makes sense

If the meter test hints at water escaping but you cannot find the source, or you are heading off for several weeks and want certainty rather than a nagging doubt, a short professional leak survey is worth considering. Modern leak detection in London is non-invasive: acoustic listening equipment, thermal imaging and tracer methods let an engineer pinpoint a hidden leak without ripping up floors or knocking through walls on spec. The goal is to find the exact spot first, so any repair is targeted and minimal.

We work on a no find, no fee basis, which means the survey itself carries no risk to you: if there is genuinely nothing to find, you have not paid for a fruitless dig, and you leave for your holiday knowing the meter test result was a false alarm rather than a warning you ignored. As a general guide, a professional survey costs a fraction of what a single serious escape-of-water repair runs to, and the peace of mind ahead of a long absence is often the deciding factor for people who book one.

None of this is about paranoia. It is about spending an hour on sensible preparation so that the worst that can happen while you are away is a slightly dusty return, rather than a soaked ceiling, warped floors and a fight with your insurer. Turn the water off, check the hoses, keep the heat ticking over in winter, and let someone keep an eye on the place. Then go and enjoy your holiday.