How much water does a small leak waste?

More than most people expect. A tap dripping once a second wastes roughly 5,500 litres a year. A leaking toilet — one of the most common hidden leaks — can waste 200 to 400 litres a day, which is over 100,000 litres a year. If your home is on a water meter, that flows straight onto your bill, so a "small" leak can quietly cost you a meaningful amount before you even count the damage.

Will home insurance cover damage from a leak?

It depends on the cause and how long it ran. Most policies cover sudden "escape of water" — a pipe that bursts without warning. But damage caused by a slow leak that developed over time, or one you knew about and did not fix, is often excluded as a maintenance issue or "gradual damage". This is exactly why ignoring a small leak is risky: you can end up paying for damage your insurer will not.

How can I tell if I have a hidden water leak?

Watch for an unexplained rise in your water bill, a persistent musty smell, damp patches or staining on walls and ceilings, peeling paint or wallpaper, a drop in water pressure, or the sound of running water when everything is off. A simple test: take a water meter reading at night and again in the morning with no water used overnight — any change indicates a leak. If you suspect one but cannot find it, a plumber can carry out leak detection without ripping the house apart.

Is a dripping tap really worth fixing straight away?

Yes — for two reasons. First, the waste: a constant drip adds up to thousands of litres a year and shows on a metered bill. Second, a dripping tap usually means a worn washer or valve that will only get worse, and the constant moisture can damage the basin, worktop, or the cupboard beneath. Fixing it early is a £80–£150 job; leaving it can mean replacing units or worktops later.

How quickly does water damage get worse?

Faster than people assume. Within hours, water spreads through porous materials like plaster and chipboard. Within days, timber starts to absorb moisture and swell. Within a couple of weeks of continuous exposure, mould can begin to grow, and structural timber can start to rot over weeks to months. The cost curve is steep — what is a simple repair in week one can be a multi-trade job within a year.

Can a small leak cause mould?

Yes. A persistent leak keeps surrounding materials damp, and mould needs only moisture, warmth, and time to take hold — often within two to three weeks. Black mould is more than cosmetic: it damages decoration and belongings and can affect breathing, especially for children, older people, and anyone with asthma or allergies. Stopping the leak early prevents the conditions mould needs.

The Real Cost of Ignoring a Small Leak

A weeping joint or a dripping tap feels like something to deal with later. But water damage compounds — and the £100 repair you put off can become a £5,000 one. Here is what a small leak really costs if you leave it.

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Why a Small Leak Is Not a Small Problem

Four reasons that drip deserves attention now, not later.

A "small" drip wastes more than you think

A tap dripping once a second wastes around 5,500 litres a year. A slow toilet leak can waste 200 to 400 litres a day — silently, on your water bill if you are metered. Small leaks are rarely as small as they look on the bill.

Damage compounds, it does not stay still

Water finds the path of least resistance and keeps going. A pinhole leak behind a wall does not wait politely — it soaks plaster, rots timber, and spreads. The repair you could have had for £100 becomes a £1,000+ job the longer it runs.

Hidden leaks attack the structure

Under floors and inside walls, a leak rots joists, corrodes pipework, and softens plaster long before you see a stain. By the time damp shows on a ceiling, the damage above it is usually well established.

Insurers may not cover slow leaks

Home insurance typically covers sudden "escape of water", but many policies exclude damage from a leak that developed gradually and was not dealt with. Ignoring a known leak can be treated as a failure to maintain — and your claim refused.

How the Cost Grows Over Time

The same leak, left longer. Watch how the bill climbs the further down you read.

Week one — the easy fix

£80–£150

A dripping tap, a weeping joint, or a running toilet caught early. Usually a washer, a valve, or a short visit from a plumber. Annoying, cheap, done.

A few months in — damp and staining

£300–£700

The leak has wet plaster, lifted paint, or stained a ceiling. Now you are paying for the plumbing repair plus drying out, replastering, and redecorating the affected area.

Unchecked for a year — structural damage

£1,500–£5,000+

Rotten floorboards or joists, blown plaster across a wall, damaged kitchen units, possibly electrics. The repair now involves more than one trade and the original drip is a footnote.

Worst case — mould and health

£5,000+ and ongoing

Persistent damp breeds black mould, which damages belongings and affects breathing — a particular risk for children, the elderly, and anyone with asthma. Remediation, ventilation, and full reinstatement add up fast.

Figures are typical UK ranges for guidance — the actual cost depends on the leak, the materials affected, and how long it has run.

Early Warning Signs to Catch It Cheap

Spot a leak at this stage and you are looking at the small bill, not the big one.

Your water bill creeps up for no reason

If you are metered, an unexplained rise is one of the earliest signs of a hidden leak. Take a meter reading last thing at night and first thing in the morning with no water used — any movement points to a leak somewhere.

A musty smell or patch of damp

A persistent musty smell, a tide mark on a wall or ceiling, or paint and wallpaper that bubbles or peels all suggest water is getting somewhere it should not. Trust your nose before you can see the stain.

Low pressure or warm patches on the floor

A drop in water pressure can mean water is escaping before it reaches the tap. An unexplained warm patch on the floor can signal a leak on a hot pipe or heating circuit beneath it.

The sound of running water when nothing is on

A faint trickle or hiss when every tap and appliance is off is a classic sign of a leak on the supply or central heating. Do not ignore it because you cannot see the source — that is exactly when to get it traced.

Don't Ignore These Signs

Each of these points to a leak that is already costing you — get it looked at.

A stain that keeps coming back after you paint over it
A boiler or heating system that needs topping up with water more than once or twice a year
Cracked or hollow-sounding tiles around a bath or shower
A toilet that hisses or refills on its own between uses
Damp or efflorescence (white powder) on internal walls
A meter that keeps ticking over when all water is switched off

Small Leak FAQs

Catch a Leak Early with an Exmouth Plumber

The cheapest leak is the one you deal with today. Our directory lists local plumbers who can trace a hidden leak and fix it before it turns into a repair job for three trades.

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Suspect a hidden leak? Read 5 signs of a hidden water leak and how leak detection works. For burst or damaged pipes see pipe repair, and for typical prices our plumber costs guide.