A public utility shall keep complete maps, plans and records of its entire distribution and other system showing the size, character and location of each main, district regulator, expansion joint, street valve and trap and each service connection, together with other information that may be necessary. The maps, plans and records required by this section shall be kept up to date so that the utility may furnish promptly and accurately copies of its maps or any information regarding its facilities upon request by the Commission. Special surveys to locate such facilities are not generally required if existing plans are inadequate.
52 Pa. Code § 61.27