All public and nonpublic schools that are not classified as a public water system and have not been granted a waiver shall conduct initial testing for the presence of lead in every drinking water outlet located in an occupied public or nonpublic school building. Bathroom and classroom sinks not clearly signed as not a drinking water outlet are subject to testing under this section. Testing shall be prioritized as follows: Drinking water outlets in school buildings constructed before 1988 and school buildings serving students in prekindergarten through grade 5 shall initially be tested before July 1, 2018. Drinking water outlets in school buildings constructed in 1988 or later and serving students in grade 6 through grade 8 not already subject to testing under this chapter shall initially be tested before July 1, 2019. Drinking water outlets in school buildings constructed in 1988 or later and serving students in grade 9 through grade 12 not already subject to testing under this chapter shall initially be tested before July 1, 2020. In cases where there is overlap between or among these student age specifications testing shall be conducted by the earlier specified deadline. The Department, in consultation with MSDE, may grant a deferral of initial testing from the requirements of §§A—C of this regulation, if either of the following situations apply: A deferral, not to exceed 3 years past the date stipulated in this regulation, may be granted if: The school submits a written request for a deferral on a form generated by the Department; The request documents that all drinking water outlets in the school building have been tested for the presence of lead in a manner that complies with this chapter; and The request documents that analysis by a certified laboratory confirming the most recent test results indicate that elevated levels of lead were not found in water samples from any drinking water outlet; or A deferral, not to exceed 12 months past the date stipulated in this regulation, may be granted if: The school submits a written request for a deferral on a form generated by the Department; The request documents that the school has a plan in place for testing all drinking water outlets; and The plan details actionable steps to be taken if an elevated level of lead in a drinking water outlet in the school building is found. Testing shall be conducted during the regular school year and while school is in session. All drinking water outlets must be sampled within the same school calendar year. In school buildings put into service after the effective date of this regulation, initial first-draw samples shall be performed within 1 year of the date of occupancy. Testing shall be performed during the regular school year and while school is in session. Schools shall conduct lead monitoring on every drinking water outlet at a frequency of every 3 years unless the school has been granted a waiver by the Department. Schools shall conduct lead monitoring within 1 year following substantive plumbing upgrades or renovations.