Range from the cheapest replacement of a toilet float valve £15 (Rafal Chaba based in CV22) to the dearest replacement of a float valve £46 (Able Plumbing and Heating based in NN7).
Comparing plumbers estimates for replacing a toilet float valve in the cistern tank gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to replace a toilet float valve in NN11 by posting a job with HaMuch and we will send it to plumbers in NN11.