Loft Water Tank Leaks — Ball Valve & Overflow Repair
Ceiling staining in the loft? Water running down the overflow outside? A failed ball valve or split overflow pipework can flood a ceiling in minutes. Our NVQ Qualified engineers diagnose the fault and carry out compliant repairs fast.
TRANSPARENT PRICING
Clear, upfront estimated cost for loft tank repairs
Estimated repair cost
£250 – £550
Subject to property location & complexity
Standard call-out
£150
Attendance + first hour on site
Additional labour
£75/hr
Per hour or part hour thereafter
What's included in the estimate
Any additional parts or extended labour required beyond the estimate will be quoted and agreed before we proceed. Urgent parts may reflect sourcing and delivery costs.
COMMON CAUSES OF LOFT TANK LEAKS
Ball valve failure
The ball valve (float valve) shuts off the water when the tank fills. Over time, limescale build-up, perished washers, material fatigue or a seized mechanism stop it from closing — water keeps flowing in and runs out of the overflow continuously. Our engineers replace the valve with a correctly rated unit matched to your system pressure.
Overflow pipework failure
Overflow pipework can split, corrode, freeze and fracture, or come loose at a joint — letting water escape into the loft space instead of safely outside. We inspect the full run, replace damaged sections and verify the pipe diameter is sized to handle worst-case fill rates.
WATER REGULATIONS COMPLIANT INSTALLATIONS
A loft tank leak is often a warning sign of an outdated or incorrectly configured system. All remedial work is carried out in accordance with the Water Supply (Water Fittings) Regulations 1999.
Compliant Cold Water Storage Tank — Schematic
Indicative schematic only — not to scale. Actual installations vary by property.
Correct air gaps
Adequate backflow prevention to protect your mains-fed drinking water from contamination.
Overflow sizing
Overflow pipework diameter verified to handle worst-case fill rates without flooding.
Ball valve specification
Correctly rated float valve selected for system pressure and tank capacity.
Structural support
Tank base and supports inspected for the full load of a filled cold water storage tank.
Thermal insulation
Tank and pipework insulated to modern energy-efficiency and frost-protection standards.
STOP THE DAMAGE BEFORE IT SPREADS
A leaking loft tank doesn't just waste water — it saturates loft insulation, stains and softens ceilings, and can track down into electrical wiring and downstairs rooms. The longer it runs, the higher the repair bill. Shut off the water supply to the tank at the isolating valve if safe to do so, contain the water with buckets, and call us immediately.
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FREQUENTLY ASKED QUESTIONS
How much does it cost to repair a leaking loft water tank?
A typical emergency call-out and remedial repair for a leaking cold water storage tank in the loft — including ball valve or overflow pipework failure — costs between £250 and £550, subject to property location and the complexity of the repair. The standard £150 call-out covers the first hour of labour on site.
What causes a loft water tank to leak?
The two most common causes are a failed ball valve (float valve) that no longer shuts off the water supply — causing the tank to overflow — and a failure or leak in the overflow pipework itself. Limescale build-up, material fatigue and corrosion are frequent contributors.
Do you repair cold water storage tanks to Water Regulations standards?
Yes. All remedial work is carried out in accordance with the Water Supply (Water Fittings) Regulations 1999, including correct air gaps for backflow prevention, appropriately sized overflow pipework, structural support checks and thermal insulation.
BOOK YOUR LOFT TANK REPAIR NOW
Don't wait for the ceiling to give way. Book online in 60 seconds or call us direct — our NVQ Qualified, Gas Safe Registered engineers are on the way.
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