Is a Boiling Water Tap Worth It?

Updated July 2026 · Emergency Plumber Chelsea

What a boiling water tap is. It is a kitchen tap, or a small separate tap, that dispenses water at or very close to boiling from a heated tank in the cupboard below. Many are combined with a normal mixer, so one tap gives hot, cold and boiling water; some also offer filtered chilled or sparkling water from extra units. An instant hot water tap is sometimes used to mean the same thing, and sometimes a tap giving very hot but not boiling water, so check the maximum temperature before you buy.

Where they earn their keep. Boiling water on demand is useful for hot drinks, pasta and vegetables, blanching, and cleaning pans. You no longer wait for a kettle or boil more water than you need, and the kettle leaves the worktop. Households that make a lot of hot drinks, families, and people with limited grip or mobility who struggle to lift a full kettle tend to get the most from one.

Where they disappoint. If you only boil a kettle a couple of times a day, the convenience is small compared with the cost of the tap, the installation and the filters. The tank keeps water hot around the clock, so it uses some electricity even when you are not using it; manufacturers publish a standby figure, and it is worth comparing models on it. And the tank has a limited capacity, so filling a large pan repeatedly can run the boiling supply down until it reheats.

What it needs under the sink. Before choosing a tap, open the sink cupboard. You need space for the tank, and often a filter cartridge and an inlet valve set, alongside the waste trap, any water softener or filter already there, and in many kitchens a dishwasher or washing machine connection. Chilled or sparkling units need more space again. The tank needs a cold mains water supply with an isolation valve, and a switched electrical socket within reach of the tank's cable. If there is no socket in the cupboard, one has to be added by an electrician. The worktop needs a suitable hole, and cutting stone, quartz or marble is usually done by the worktop fabricator rather than on site.

Water pressure and the inlet valves. Boiling water taps are designed to run within a range of incoming mains pressure set by the manufacturer. Most kits include an inlet valve set that controls the pressure reaching the tank and deals with expansion as the water heats. It must be fitted as supplied, and any discharge must go somewhere safe. Where mains pressure is high, a pressure reducing valve on the incoming supply becomes relevant; in a top-floor flat it can be too low, which is worth checking before buying.

Hard water is the ongoing cost. London's water is hard, and heating it to boiling makes limescale form quickly in the tank and the outlet. That is why most boiling water taps use a filter cartridge that needs replacing on a schedule, and why skipping the filter leads to slower flow, spitting at the outlet, scale flakes in your cup and, eventually, a tank that needs descaling or replacing. Budget for cartridges before you decide. Our guide to hard water and limescale explains how scale behaves in London homes.

Safety with children and guests. Near-boiling water from a tap is a scald risk, so every reputable boiling tap has a child-resistant control that has to be pushed and turned, or pressed twice, before it dispenses. Some are insulated so the spout does not get hot. If you have young children or regular visitors who will not know the tap, choose a model with a clear, deliberate control and show people how it works. Hot-only spouts should not be used to fill a baby's bath or similar.

What fitting one involves. On a straightforward installation into an existing kitchen, the old tap comes out, the worktop hole is checked or enlarged, the new tap goes in, and the tank, filter and inlet valves are fitted and connected to the cold mains with isolation valves. The tank is then filled, flushed and heated, and every joint is checked for leaks. Most of the time and cost goes into awkward cupboards, moving existing pipework, dealing with seized old isolation valves, and adding a socket. It does not involve gas, so it is not Gas Safe work, but it does involve both plumbing and electrics.

Common problems after installation. Most call-outs are for a slow or spitting boiling outlet, which is usually a filter that is due or scale in the outlet; a tap that drips or leaks at the base, which is the same kind of fault as any mixer tap; or water appearing in the cupboard, which needs finding quickly because it may be a connection, the inlet valve set discharging, or the tank itself. If water is collecting under the sink, our guide to a leak under the kitchen sink shows how to trace it, and our guide to a leaking kitchen mixer tap covers the tap itself.

So, is it worth it? Yes if you boil a kettle often, value the counter space, have the room and the socket under the sink, and will keep up with the filters. No if your use is light, your cupboard is already full, or you want a set-and-forget appliance. If you are refitting the kitchen anyway, planning the tank, socket and water supply at the design stage makes the installation simple. If what you want is ordinary hot water at a tap far from the boiler, rather than boiling water, a point of use water heater is the better fit.

Getting one fitted. Emergency Plumber Chelsea checks your cupboard space, mains pressure and pipework, fits the tap, tank, filter and valves to the manufacturer's instructions, and tests everything before we leave. There is no call-out fee on jobs over 3 hours. See our kitchen plumbing service or call 020 3002 6667 for SW3, SW10, Knightsbridge, Sloane Square, South Kensington and Fulham.

Quick tips

• Measure the sink cupboard before choosing a tap; the tank, filter and valves need more space than people expect.
• Check there is a socket in the cupboard, or budget for an electrician to add one.
• In hard-water London, treat filter cartridges as a running cost and change them on schedule.
• Compare the manufacturer's standby energy figures between models, not just the tap price.
• Fit the inlet valve set supplied with the tank; leaving it out can cause leaks and void the warranty.

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