A broken boiler is usually an emergency if you've lost heating or hot water completely, especially in cold weather or with children, older people or anyone unwell at home. A suspected gas leak or carbon monoxide problem is always an emergency, and needs immediate safety action, not a routine booking. Tell us what's happened and we'll pass your enquiry to a local Gas Safe registered engineer.
This page covers what counts as urgent, what it costs, and the one situation where you shouldn't wait for an engineer at all.
What is classed as an emergency repair for a boiler?
A genuine boiler emergency is usually a complete loss of heating or hot water, a suspected gas leak, or signs of carbon monoxide. Engineers generally treat "no heat and no hot water together" as more urgent than one or the other, and treat it as more urgent again if the household includes young children, older people or anyone with a health condition.
A boiler that's working but making an odd noise, or has slightly low pressure, usually isn't an emergency and can wait for a normal appointment. Whatever brand you have, Worcester Bosch, Vaillant, Baxi or another, the same rule of thumb applies. The purpose of flagging a job as urgent is to get an engineer out sooner, so it's worth being specific about what's actually happened when you enquire, and to choose the urgent option only when it genuinely applies.
How much does an emergency boiler repair cost?
Emergency boiler repairs typically cost £225 to £675, averaging around £450, more than a routine repair because engineers are often working unsociable hours and parts get sourced at short notice. A standard, non-emergency repair averages £300, typically £120 to £750 depending on the fault and whether parts are needed.
The specialist you're matched with will confirm their own price before starting any work, so you'll know the cost before you commit to the job.
Who do I call if my boiler stops working?
For anything other than a suspected gas leak, a local Gas Safe registered engineer is who you want, and that's who we'll pass your enquiry to. Tell them what's happened (no heat, no hot water, both, or something else) and whether it's urgent, so they can judge how quickly to come out.
If you smell gas or suspect carbon monoxide, don't wait to book an engineer at all. We recommend calling the National Gas Emergency Service on 0800 111 999 straight away, turning off the gas at the meter if it's safe to do so, avoiding other gas appliances in the meantime, and opening windows and doors.
Is it an emergency if my boiler is leaking?
A leak is usually not a gas safety emergency, but it can become a bigger problem quickly if water reaches electrics or causes damage, so it's worth treating as urgent rather than routine. Turn off the boiler and, if you can locate it safely, the water supply to it, while you wait for an engineer.
The exception is if the leak smells of gas rather than water, or you notice soot staining, a pilot light that's gone yellow instead of blue, or anyone in the house feels unusually unwell, headaches, dizziness or nausea. Those are signs of carbon monoxide, not a water leak, and need the gas emergency number, not a routine repair booking.
Questions people ask
Why is my boiler leaking water from underneath?
Water underneath the boiler usually comes from a loose seal, a failed internal part, or pressure that's been too high and has triggered the pressure relief valve to discharge. Older boilers with internal corrosion are more prone to this. A Gas Safe registered engineer can trace the source once they've had a look, since several different parts can cause the same symptom.
Is it expensive to fix a leaking boiler?
It depends on the source. Boiler repairs in general cost £120 to £750, averaging £300, and a straightforward seal or valve replacement sits toward the lower end of that range. Older boilers with corrosion-related leaks can cost more if several parts need replacing. An engineer can give you a firm price once they've identified where the leak is coming from.
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