The provision of the Fire Service in its functional area, including the establishment and maintenance of a fire brigade is a statutory function of individual fire authorities under section 10 of the Fire Services Act 1981 and 2003. Under section 35(3) of the Act, it is a matter for each local authority to determine whether to charge users or beneficiaries of a service that their fire authority provides, including attendance at fire incidents.
In many cases the householder/premises owner may recoup charges for attendance of the fire brigade at incidents from relevant insurance polices.
I also understand that fire authorities operate a waiver scheme in respect of call-out charges as the question mentions. Each case is considered on its merits and partial waivers as well as deferred payment options are considered as appropriate. Further information on the operation of these schemes is available from individual local authorities, many of which publish details on their websites or provide information on request.