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✅ HelpfulValves & Stopcocks
Ball Valves & Float Valves
Ball valves (also called float valves) are the automatic filling valves inside your toilet cistern and cold water storage tanks. They open when water level drops and close when it rises — entirely automatic, no electricity.
⚙️ How they work
A ball valve has a hollow plastic float on an arm. As water drains (when you flush), the float drops, pulling the arm and opening the valve. Water flows in. As the cistern refills, the float rises and eventually closes the valve. When the washer inside wears out, the valve doesn't close properly and water runs continuously into the overflow.
🔍 Signs of a failing ball valve
Water dripping or running from the overflow pipe on your outside wall. A continuous hissing after a toilet flush that never fully stops. Water level in the cistern above the overflow pipe.
🛠 Quick check
Lift the float arm upward with your finger. If the water stops running, the valve is working but the level is set too high — bend the float arm slightly downward. If water keeps running even with the arm lifted fully, the washer is worn and needs replacing.
Running toilet fact: A constantly running toilet wastes around 400 litres of water per day — that's roughly £1 a day on your water bill.
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General guidance only — not a substitute for professional advice. Always consult a qualified engineer if you are unsure. Gas work must only be carried out by a Gas Safe registered engineer. Unvented (pressurised) hot water systems must be worked on by a G3-qualified engineer. We accept no liability for any loss, damage, or injury arising from the use of this information.
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