A consumer shall not be required under these by-laws to Alter or renew any pipe, fitting, apparatus or other component forming part of the water-service and lawfully existing and in lawful use on ay premises immediately before the date of these by-laws becoming applicable to such premises, or to construct or provide any addition thereto, unless and until such pipe, fitting, apparatus or other component is so defective or in such a condition or position as to cause waste, undue consumption, misuse, erroneous measurement or pollution or risk of pollution of the water supplied by the local authority.