How much does a power flush cost?
Cold patches at the bottom of radiators usually mean sludge. What a power flush involves and how to see a typical price for your home.
Tell us about your home and we'll show the typical UK price range for this job, what's involved and what to ask, in about 20 seconds. The job is already filled in: change anything that's different.
What the job involves
- Checking the system: sometimes bleeding radiators or balancing is all that's needed.
- Flushing the system with a pump and cleaning chemicals, radiator by radiator.
- Adding inhibitor, and often a magnetic filter to keep it clean.
What moves the price
- Number of radiators.
- Whether a magnetic filter is fitted at the same time.
- Old systems that need valves or radiators replaced.
Before you say yes
- Gas Safe registration if they touch the boiler.
- Before and after water quality readings.
Questions people ask
Do I need a power flush or just bleeding?
If radiators are cold at the top, bleed them. If they are cold at the bottom or the water is black, a flush is usually needed.
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General guidance from LocalWins, last checked October 2026. It is not legal advice or a planning decision, and every home is different: confirm anything important with your council or a qualified professional.