A toilet that runs continuously after flushing wastes hundreds of litres of water a day. Here are the three most likely causes and what to do about each one.
The fill valve controls the water supply into the cistern after a flush. When it wears out, it cannot shut off completely — so water keeps trickling in and the overflow pipe runs continuously.
How to check
Lift the cistern lid. If water is running into the overflow pipe at the back of the cistern, the fill valve is the likely culprit. You may also hear a constant hissing sound even when the toilet has not been flushed recently.
Hard water note: In Ashford, limescale builds up on fill valve components over time. If your toilet is more than 8–10 years old and has never had the fill valve replaced, this is the most likely cause.
The flush valve seal sits at the bottom of the cistern and seals the opening between the cistern and the bowl. When this seal wears, water seeps slowly from the cistern into the bowl — causing the fill valve to top up constantly.
How to check
Put a few drops of food colouring into the cistern and wait 15 minutes without flushing. If colour appears in the bowl, the flush valve seal is leaking. This is sometimes called a silent leak because you cannot always hear it.
Older toilets use a float arm to detect when the cistern is full. If the arm is set too high, or if the float has cracked and filled with water, the cistern never reaches the cut-off level and the fill valve never shuts off.
How to check
Lift the cistern lid. If you can see a horizontal arm with a ball float, gently lift the arm by hand. If the water stops running, the float arm is set too high. If the ball feels heavy or you can hear water sloshing inside it, the float has cracked.
The three most common causes are a worn fill valve, a faulty flush valve seal, or a float arm set too high.
Most running toilet repairs are straightforward fixed-price jobs. Flow Right Plumbing provides a fixed price before any work is agreed.
A continuously running toilet can waste between 200 and 400 litres of water per day — roughly 6,000 to 12,000 litres per month.
Yes. In hard water areas like Ashford, limescale builds up on fill valve components and flush valve seals, preventing them from seating correctly.
Call a plumber if the toilet runs continuously, if you can hear water trickling into the bowl when not flushed, if the cistern takes more than 3 minutes to refill, or if you have a concealed cistern.
Yes. Flow Right Plumbing covers Ashford and surrounding villages. We carry out fill valve replacements, flush valve seal replacements, and full cistern overhauls at a fixed price.
Send a photo of the cistern on WhatsApp and we will let you know what the fix is and what it will cost — fixed price, no call-out fee.
Fixed prices · No call-out fee · 1-year guarantee
Related help
Read the guide that matches the symptom, see the repair service, or upload a photo for a fixed-price assessment.
You can also send a photo on WhatsApp if that is easier.