Construction defect · Defects & construction flaws
Plumbing defects: leaks, pressure, drainage in new-builds
Severity ⚠ High
Reporting deadline 90 days
Warranty Two-year + ten-year
Responsibility Plumber
How to detect a plumbing defect?
A compliant plumbing installation must be watertight under pressure and at rest, drain quickly, deliver pressure at each tap between 2 and 5 bar, and a sufficient flow rate (minimum 12 L/min at a kitchen tap). Test: open all taps simultaneously (pressure drop < 30% acceptable), check under each siphon (no leaks, no damp traces), listen for the booster pump constantly running (= network micro-leak), watch the meter for 24h without use (if it turns = leak). Drainage: emptying a full sink should drain in less than 30 seconds. Check inspection chambers and the position of the non-return valve where applicable.
Before — compliant
pressure 3 bar · no leak · fast drainage
Watertight · compliant pressure · sufficient flows
⚠ After — defective
leak under sink · pressure 1.2 bar
Siphon leak · low pressure · to be redone
Reporting procedure in 4 steps
A leak or hydraulic defect can cause major damage in a few days. Act fast to preserve your remedies.
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1
Cut off and document
Immediately close the mains stopcock in case of leak. Photograph before and after. Note meter reading, date, exact conditions (shower in use, recent frost, etc.).
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2
Pressure and watertightness test
Pressure gauge on incoming water (between 2 and 5 bar). Flow meter at tap (12 L/min min kitchen). 24h test without use: if meter turns = network leak.
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3
Formal notice
Registered letter to the plumber AND the contractor within 90 days. Attach photos, measurements, invoices for collateral damage if any. Demand urgent action within 7 days.
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4
Plumbing expert assessment
Independent plumber expert in case of dispute. Endoscopic camera, pressure measurements, smoke test. Admissible report · from €380 VAT incl. Cost recoverable.
Who pays for the repair? Responsibility table
The plumber is responsible for their installation. The contractor is jointly liable. Collateral damage: home insurance possible.
Fitting / siphon leak
✓ two-year warranty
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Hidden leak wall / slab
✓ ten-year liability
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ARI + structural
Insufficient pressure (< 2 bar)
✓ two-year warranty
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Slow drainage / backflow
✓ two-year warranty
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Get an inspection
Independent plumbing diagnosis
Endoscopic camera · pressure test · admissible report · €380 VAT incl.
FAQ
Common questions about plumbing
My water meter turns slightly at night when nothing is open. Abnormal?+
Yes, leak confirmed. A WC cistern leaking drop by drop or a micro-leaking fitting. Close valve by valve to locate it. Report under two-year warranty and demand immediate repair.
My pressure is only 1.5 bar. What should I do?+
Insufficient pressure (standard 2-5 bar). Possible cause: badly adjusted reducer, faulty building distributor, or undersized piping. Report under two-year warranty and demand correction.
My WC rises when I fill the bathtub. Really serious?+
Very serious. Poorly vented or undersized drainage. Sanitary risk (bacterial backflow, bad smells). Ten-year defect because it renders the property unfit for use. Report immediately.
How much does a complete plumbing diagnosis cost?+
Between €380 and €550 VAT incl. Includes: pressure and flow test, leak detection with tracer gas or camera, drainage check, DHW verification. Cost recoverable if defect confirmed.
Is a hidden leak in a wall after 6 months covered?+
Yes, ten-year liability. An embedded pipe must last 30+ years. Early leak = hidden defect. The contractor must open, repair, and refinish (paint, tiles). Structural-damage insurance can speed things up.