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    Why Does My Toilet Keep Running? Causes, Costs and Fixes

    A constantly running toilet wastes thousands of litres and inflates your Johannesburg water bill. The common causes — flapper, float, fill valve — and how to fix it.

    8 June 2026 6 min read
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    A toilet that whispers and refills on its own all day is easy to ignore — until the water bill lands. A running toilet is one of the most common (and most wasteful) plumbing faults in Johannesburg homes, and most fixes are cheap.

    What is actually happening

    A running toilet means water is constantly escaping from the cistern into the bowl, so the cistern never stops refilling. Three parts are usually responsible:

    • The flapper or outlet seal — worn or warped, it no longer seals, so water trickles into the bowl.
    • The float — set too high, water rises past the overflow and drains away continuously.
    • The fill valve — faulty, it never fully shuts off.

    What it is costing you

    A continuously running toilet can waste 200–400+ litres a day — thousands of litres a month, plainly visible on your bill. It is one of the most common hidden reasons a water bill suddenly jumps.

    The quick test

    Put a few drops of food colouring in the cistern and wait ten minutes without flushing. If colour appears in the bowl, the flapper or seal is leaking and needs replacing.

    Fix it cheaply now

    Some fixes are simple DIY — adjusting the float or swapping a flapper. If the fill valve is faulty or it keeps recurring, a plumber resolves it properly and checks nothing else is feeding the leak. See toilet repairs or, if your bill has spiked unexpectedly, our leak detection service. Book a fix.

    Frequently Asked Questions

    A toilet runs when water keeps leaking from the cistern into the bowl. The usual causes are a worn flapper or seal, a float set too high, or a faulty fill valve that does not shut off. Most are inexpensive parts, but a running toilet can waste hundreds of litres a day until fixed.

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