--- title: "How to Turn Off Water at the Mains | Reactive" description: "Find your internal and external stop taps, test they actually work, and shut off your water in 30 seconds when it matters — from a Gas Safe plumber." lang: en-GB json-ld: | [ { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What if my stop tap is seized and won't turn?", "acceptedAnswer": { "@type": "Answer", "text": "Don't force it — you'll snap it and lose all control. Use the external stop tap instead, then book a plumber to replace the internal one. Replacement is a quick fixed-price job, typically including a modern quarter-turn ball valve." } }, { "@type": "Question", "name": "Why does water keep coming through after I've turned the stop tap off?", "acceptedAnswer": { "@type": "Answer", "text": "Three possibilities: (1) you turned the wrong valve — many properties have multiple stop taps for different sections, only one is the master; (2) the stop tap isn't fully closing — it's worn and needs replacement; (3) the leak is upstream of the stop tap (rare but possible on the rising main itself) — call us." } }, { "@type": "Question", "name": "Do I need a key for the external stop tap?", "acceptedAnswer": { "@type": "Answer", "text": "Almost always, yes. The valve sits 30–60cm down inside the chamber, well below the surface. A long-handled stopcock key is the proper tool; a long flathead screwdriver works in a pinch on some valve types." } }, { "@type": "Question", "name": "Is the external stop tap mine or the water company's?", "acceptedAnswer": { "@type": "Answer", "text": "Strictly, the external stop tap belongs to the water company and is for their use, but they generally don't object to homeowners using it in emergencies. The pipe from there to your house is your responsibility; the pipe before it is theirs." } }, { "@type": "Question", "name": "Should I leave my heating on if I shut the water off in winter?", "acceptedAnswer": { "@type": "Answer", "text": "If you're shutting it off because of a leak, leave the heating on if possible — it stops other pipes freezing while you wait. If you're shutting it off for an extended absence in winter, drain the system fully (every tap and the boiler drain valve) and turn the heating off too." } }, { "@type": "Question", "name": "Can I shut off just the cold water and leave the hot?", "acceptedAnswer": { "@type": "Answer", "text": "On a combi boiler, no — turning off the cold mains turns off the hot supply too. On a system or regular boiler with a hot water cylinder, you can isolate just the cold mains and continue using the stored hot water in the cylinder until it runs out (usually a few hours of normal usage)." } } ] }, { "@context": "https://schema.org", "@type": "Article", "@id": "https://reactiveplumbing.co.uk/guides/how-to-turn-off-water-at-the-mains#article", "headline": "How to Turn Off Your Water at the Mains", "description": "Find your internal and external stop taps, test they actually work, and shut off your water in 30 seconds when it matters — from a Gas Safe plumber.", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://reactiveplumbing.co.uk/guides/how-to-turn-off-water-at-the-mains" }, "author": { "@type": "Person", "name": "Carl Eddershaw", "jobTitle": "Director & Lead Engineer", "worksFor": { "@id": "https://reactiveplumbing.co.uk/#localbusiness" } }, "publisher": { "@id": "https://reactiveplumbing.co.uk/#organization" }, "datePublished": "2026-05-01", "dateModified": "2026-05-01", "image": "https://reactiveplumbing.co.uk/favicon.png", "inLanguage": "en-GB" }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://reactiveplumbing.co.uk" }, { "@type": "ListItem", "position": 2, "name": "Plumbing Services", "item": "https://reactiveplumbing.co.uk/plumbing-services" }, { "@type": "ListItem", "position": 3, "name": "Emergency Plumbing", "item": "https://reactiveplumbing.co.uk/emergency-plumbing" }, { "@type": "ListItem", "position": 4, "name": "How to Turn Off Your Water at the Mains", "item": "https://reactiveplumbing.co.uk/guides/how-to-turn-off-water-at-the-mains" } ] }, { "@context": "https://schema.org", "@type": "Person", "name": "Carl Eddershaw", "jobTitle": "Director & Lead Engineer", "image": "https://reactiveplumbing.co.uk/favicon.png", "worksFor": { "@id": "https://reactiveplumbing.co.uk/#localbusiness" }, "knowsAbout": [ "Gas Safe boiler installation", "OFTEC oil heating", "LPG installations", "Plumbing & drainage" ] } ] --- Gas Safe Registered · OFTEC Registered · Checkatrade Verified 9 Rutherford Court, Corby NN17 4SJ [info@reactiveph.co.uk](mailto:info@reactiveph.co.uk) [![Reactive Gas Heating & Plumbing logo](/__l5e/assets-v1/51d713a4-18a4-4b5f-96fb-2fcce169e56c/reactive-logo.png)](/) ServicesAreasGuides[About](/about)[Our Work](/our-work)[Plans](/maintenance-plans)[Reviews](/reviews)[Contact](/contact) [24/7 Call 07915 906262 ](tel:+447915906262)[Fixed Boiler Quote](/boiler-quote) 1. [Home](/) 2. [Plumbing Services](/plumbing-services) 3. [Emergency Plumbing](/emergency-plumbing) 4. Guide Guide · Emergency Plumbing # How to Turn Off Your Water at the Mains Knowing exactly where your stop tap is — and that it actually works — saves thousands in flood damage. This is a 5-minute job to do today, before you need it. 6 min read By Carl Eddershaw, Director & Lead Engineer Last updated May 2026 Quick answer **Your internal stop tap is most often under the kitchen sink, in a downstairs cupboard, or in the utility room.** Turn it clockwise to shut off the water. **Your external stop tap is in the pavement or front garden inside a small marked cover** (often labelled "W") and needs a long key. Test both today — if the internal one is seized, fix it before you need it, not during a flood. ## Where to find your internal stop tap On most UK properties, the internal stop tap is on the rising main — the cold water pipe that comes in from the street. It's typically located in one of these spots: - **Under the kitchen sink** — most common location in 1960s+ properties - **In the utility room** — common in newer-build homes - **In a downstairs cupboard** — under the stairs, hallway airing cupboard, or boiler cupboard - **In the cellar or garage** — older Victorian and Edwardian terraces - **Behind a kitchen kickboard or fridge** — modern flats and apartments It will look like a brass or chrome valve with a round handle (older style) or a quarter-turn lever (newer style). On older properties the round handle may be paint-stuck — if it won't move with reasonable hand force, don't force it (you'll snap it). Call a plumber to free or replace it before you need it for an emergency. ## How to actually use it **Round-handle stop tap:** Turn clockwise until it stops. It's a multi-turn valve — usually 4–6 full rotations. Don't over-tighten at the end; finger-tight plus a small extra is enough. **Quarter-turn lever:** Rotate the lever 90 degrees so it sits at right angles to the pipe. When the lever is in line with the pipe, the valve is open; perpendicular, closed. To test it works: turn it off, then open a cold tap somewhere in the house. The flow should stop within 10–15 seconds (the pipework still holds some water that drains out first). If the tap keeps running indefinitely, the stop tap isn't fully closing — needs replacement. **Test your stop tap once a year** — exercising it stops it seizing, and confirms it works. The worst time to discover a seized stop tap is during a burst pipe at 2am. ## Where to find your external stop tap Your external stop tap is the water company's shut-off, located between your property and the water main in the street. It sits inside a small chamber, usually: - In the pavement directly outside the front of the property - In the front garden, near the boundary or path - Just inside the property boundary, sometimes covered by a paving slab The cover is small (around 10cm × 10cm), usually metal or plastic, often marked "W" (Water) or with the water company's logo. Lift it with a flathead screwdriver in the slot. Inside you'll see a stop tap deep in the chamber — you'll need a long-handled stopcock key (any plumber's merchant sells one for £10–£15) or, in a pinch, a long-handled flat screwdriver that fits the slot. **Use the external stop tap when:** the internal one is seized or missing, water is reaching the internal stop tap and you can't safely access it, or you're isolating the property fully (e.g. for an extended absence in winter). ## What to do once the water is off For a full emergency response sequence, see our companion guide: [what to do in a plumbing emergency](/guides/what-to-do-in-a-plumbing-emergency). The short version: turn off the boiler, drain the system by opening cold taps from highest to lowest, and call a 24/7 emergency plumber if you have an active leak or burst. ## A few extra things worth doing today **Label your stop tap.** A small luggage tag tied to it saying "WATER OFF — TURN CLOCKWISE" means anyone in the house (kids, partner, house-sitter) can act in an emergency. **Buy a stopcock key now.** They're £10–£15 from any plumber's merchant or B&Q. Keep it in a known place. Trying to find one at midnight during a burst is a losing game. **Know where your boiler isolator is too.** Usually a switched fused spur immediately next to the boiler. If you have to shut the water off, you'll likely need to shut the boiler off too. **Consider a smart leak-detection valve** if you've had previous leaks or you're away from home a lot. Devices like LeakBot or Sure Petcare detect anomalous flow and alert your phone; higher-end units can shut the water off automatically. We can fit one as part of any plumbing visit. About the author ### Carl Eddershaw Director & Lead Engineer · Reactive Gas Heating & Plumbing Reactive runs from its workshop at Rutherford Court in Corby. Gas Safe registered, OFTEC registered for oil and certified for LPG, with daily on-the-tools experience installing, repairing and servicing boilers across Northamptonshire, Rutland and Leicestershire. Every guide on this site is written from real call-out notes — not generic copy. ## Frequently asked questions ### What if my stop tap is seized and won't turn? ### Why does water keep coming through after I've turned the stop tap off? ### Do I need a key for the external stop tap? ### Is the external stop tap mine or the water company's? ### Should I leave my heating on if I shut the water off in winter? ### Can I shut off just the cold water and leave the hot? Need a hand? ## Stop tap seized? Replace it before the next emergency. We replace seized stop taps in under an hour for a fixed price, including a modern quarter-turn ball valve that you'll be able to operate by hand for the next 20 years. See the full emergency plumbing service: [see emergency plumbing services](/emergency-plumbing) · [book a stop tap replacement](/emergency-plumbing) · [24/7 emergency plumber Corby](/emergency-plumbing) [See Emergency Plumbing](/emergency-plumbing) [Call 07915 906262](tel:+447915906262) Last updated May 2026 ## Keep reading [Back to Plumbing Services overview](/plumbing-services) [ Guide ### What to do in a plumbing emergency Step-by-step actions for the first 15 minutes — what to shut off, what to leave alone, what to call about. Read more ](/guides/what-to-do-in-a-plumbing-emergency)[ Service ### Hidden leak detection If your meter shows usage with everything off, you've got a hidden leak. Acoustic and thermal tracing pinpoints it without ripping floors up. 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