25 Pa. Code § 110.204 – Voluntary registration.

(a) A person, not subject to § 110.201 (relating to registration requirement), may voluntarily register with the Department the water withdrawal or withdrawal use, in accordance with the registration provisions of this subchapter.
(b) Notwithstanding § § 110.301 and 110.401 (relating to reporting requirement; and recordkeeping requirement), voluntary registrants shall monitor, maintain records and report to the Department in accordance with the other provisions of Subchapters C—E (relating to reporting; recordkeeping; and monitoring).

This section cited in 25 Pa. Code § 110.501 (relating to metering and measuring requirement).