It's now the law in Minnesota. Text below.
c) Public water suppliers serving more than 1,000 people must employ water use demand reduction measures, including a conservation rate structure, as defined in subdivision 4, paragraph (a), unless exempted under subdivision 4, paragraph (c), before requesting approval from the commissioner of health under section 144.383, paragraph (a) , to construct a public water supply well or requesting an increase in the authorized volume of appropriation. Demand reduction measures must include evaluation of conservation rate structures and a public education program that may include a toilet
and showerhead retrofit program.
Subd. 4. Conservation rate structure required.
(a) For the purposes of this section, "conservation rate structure" means a rate structure that encourages conservation and may include increasing block rates, seasonal rates, time of use rates, individualized goal rates, or excess use rates. The rate structure must consider each residential unit as an individual user in multiple-family dwellings.
(b) To encourage conservation, a public water supplier serving more than 1,000 people in the metropolitan area, as defined in section 473.121, subdivision 2, shall use a conservation rate structure by January 1, 2010. All remaining public water suppliers serving more than 1,000 people shall use a conservation rate structure by January 1, 2013.
(c) A public water supplier without the proper measuring equipment to track the amount of water used by its users, as of the effective date of this act, is exempt from this subdivision and the conservation rate structure requirement under subdivision 3, paragraph (c).