Water where it shouldn't be is one of the few jobs in the house that can't wait until next week. Yet with a leak, precious time is often lost on the wrong tradesperson: a plumber who finds that the roof is leaking, a roofer who finds a leaking central heating pipe. This article helps you in three steps: first limit the damage, then use the symptom to decide which tradesperson to call, and finally report the damage in a way that gets your insurer to contribute. If in doubt, the plumber is the safest first choice; they can rule out most causes inside the house.
The first ten minutes: limiting the damage
- Turn off the main stopcock. It is usually in the meter cupboard, the crawl space or by the water meter. If the leak stops within a few minutes, the cause is in your water supply pipes. If it keeps dripping, the water is coming from outside, from the central heating system or from a drain.
- Switch off the electricity in the room where the water is running, especially if it reaches a light, a socket or the fuse box. Switch off the relevant circuit or the main switch and do not touch wet electrical parts.
- Catch the water with buckets and towels, move furniture out of the way and lift floor coverings where you can. If the ceiling is bulging, carefully poke a small hole above a bucket so the water drains in a controlled way instead of the ceiling coming down.
- Take photos and videos before you clear anything up: the damp patch, the source if you can see it, damaged belongings and the date. This is your evidence for the insurer and for any dispute with a contractor or the neighbours.
- Check the boiler. A pressure gauge that keeps dropping or a boiler that constantly needs topping up points to a leak in the central heating system.
Symptom by symptom: which tradesperson you need
| What you see | Likely cause | Who to call |
|---|---|---|
| Damp patch on the ceiling below the bathroom or kitchen | Leaking drain, water pipe, sealant joint or tiling | Plumber; for sealant and tiles, a tiler afterwards |
| Damp patch on the ceiling of the top floor, worse after rain | Roof covering, roof penetration, lead or zinc flashing, roof window | Roofer |
| Water by or under the boiler, heating pressure drops | Leaking boiler, expansion vessel, coupling or heating pipe | Heating engineer |
| Damp patch around a radiator or in the floor above the heating pipes | Leaking radiator valve, coupling or pipe in the floor | Heating engineer or plumber with leak detection |
| Damp wall below a window or by a frame after rain | Frame junction, sealant joint, rotten timber or broken glass | Carpenter; for glass, a glazier |
| Water in the crawl space, no loss of pressure | Groundwater, leaking sewer pipe or rainwater downpipe | Plumber for the sewer; for groundwater, a contractor or specialist |
| Damp facade or interior wall, salt deposits, no clear timing | Penetrating or rising damp, poor pointing | Bricklayer or damp specialist |
| Water from an overflowing gutter running down the facade | Blocked or leaking gutter, loose downpipe | Roofer or plumber |
A few rules of thumb help you tell them apart. A leak that appears only after rain almost always comes from outside: the roof, gutter, window frame or facade. A leak that carries on continuously, even in dry weather, comes from a pipe under pressure: the water supply or the central heating. A leak that only appears during use, for example after a shower or flushing the toilet, comes from a drain, a sealant joint or a seal. If the heating pressure drops while the main stopcock is closed, the leak is in the heating system.
Who does what
The plumber is the all-rounder for water in the house: water pipes, drains, sewer connections, sanitaryware, and often zinc and lead work on gutters and roof edges as well. With an unclear leak, they can track down the source with leak detection, pressure tests and sometimes a camera inspection of the sewer, without tearing things open straight away. Many plumbers are also installers and can repair simple heating leaks in pipes and radiators.
The heating engineer is the specialist for the boiler itself, the expansion vessel, the pump and the controls. A leaking boiler, a pressure drop with no visible leak or a boiler that goes into fault after topping up is their territory. Installing, servicing and repairing a gas-fired boiler and its flue may only be carried out by a company certified to do so.
The roofer repairs roof coverings, roof penetrations, valley gutters, lead and zinc work around chimneys and dormers, and replaces broken roof tiles. With a leak in a flat roof, ask for an inspection of the whole roof surface: water can run several metres under bitumen or EPDM away from the spot where it gets in.
Leaks around window frames and glass are the domain of the carpenter and the glazier. Rot at the bottom of a frame, a sealant joint between frame and facade that has come loose, or a broken pane let in rainwater that only shows up below the window. With damp coming from the wall with no clear source, with salt deposits or flaking paint, think of penetrating or rising damp; that is work for a bricklayer or damp-proofing specialist, not for a plumber.
With larger damage, where ceilings, floors and walls need repairing, a contractor coordinates the repairs once the source has been sealed. Only carry out repairs when the structure is truly dry; a moisture measurement prevents mould from growing on under new plasterwork.
When it really is an emergency
Not every leak is an emergency. Call an emergency service straight away if water gets near electrics, if the leak doesn't stop after you have closed the main stopcock and switched off the heating, if the ceiling is sagging, if sewage is coming in or if the leak is reaching the neighbours. A dripping tap, a damp patch that has looked the same for weeks or a leak that stops once the main stopcock is turned off can wait until the next working day; that saves you a hefty evening or weekend surcharge.
An emergency is also when rogue emergency plumbers strike: companies that sit at the top of the search results, arrive quickly, quote a vague hourly rate and then present a bill out of all proportion to the work. Always ask in advance for the company name, the KvK number (Chamber of Commerce registration), the rate including call-out charge and surcharge, and do not pay in cash. How to recognise a reliable company and what to do if things go wrong is explained in How to recognise a reliable plumber and avoid emergency-job fraud.
The insurer and the neighbours
Damage to the home from a sudden leak is usually covered by your opstalverzekering (buildings insurance), and damage to your belongings by your inboedelverzekering (contents insurance). Many policies also pay for tracing the leak and the breaking-open work needed to reach the pipe, but not always for repairing the pipe itself, and usually not for damage caused by long-term neglected maintenance, such as a gutter that has been leaking for years. Check your policy terms and report the damage as soon as possible, even if you don't yet know how extensive it is. Hold off on permanent repairs until the insurer has agreed or an assessor has taken a look, unless delay would lead to more damage.
If you rent, a leak in the structure or the pipework is as a rule a matter for the landlord; report it in writing straight away. If you live in a flat, it matters whether the source is in your private part or in a shared part such as the roof or a vertical stack pipe; in the latter case it is up to the VvE (owners' association). If your leak reaches the neighbours or the other way round, the owner of the source is in principle liable; get in touch, take photos together and let both insurers settle it between themselves. You can read more about cover and liability in Renovating and insurance: buildings, CAR and liability.
Many leaks can be prevented with small maintenance tasks: clean the gutters twice a year, renew sealant edges as soon as they come loose, keep an eye on the heating pressure and paint window frames in good time. You'll find an overview per season in the maintenance calendar for your home. If you have a leak right now, you can post your job free of charge on VerbouwPro and plumbers, roofers and heating engineers from your area with a verified profile and reviews will respond.