Cold water storage tank overflowing
✅Free DIY guide — no sign-up required. Written by a qualified Gas Safe engineer.
DIY Friendly💷 £5–£40⏱ 20–45 min
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Most likely cause & what to check
1
Access the loft tank and inspect the ball valve — the float should close the valve when the tank is full.
2
If the float is waterlogged or cracked, unscrew and replace it.
3
If the valve won't shut off, the washer inside has perished — turn off the mains, drain slightly, and replace the washer (£2).
4
After repair, check the water level sits 25mm below the overflow pipe.
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