(a) No later than July 1, 2023, and updated every five years thereafter, a small water supplier serving 1,000 to 2,999 service connections, inclusive, and a nontransient noncommunity water system that is a school shall each develop and maintain, onsite, an abridged Water Shortage Contingency Plan (WSCP) that includes, at a minimum, all of the following drought-planning elements:

1. (1) Drought-planning contacts, including all of the following:

   1. (A) At least one contact at the water system for water shortage planning and response and the development of the plan.
   2. (B) Contacts for local public safety partners and potential vendors that can provide repairs or alternative water sources, including, but not limited to, local community-based organizations that work with the population in and around areas served by the water system, contractors for drilling wells, vended water suppliers, and emergency shower vendors.
   3. (C) State and local agency contacts who should be informed when a drought or water shortage emergency is emerging or has occurred.
   4. (D) Regional water planning groups or mutual aid networks, to the extent they exist.

2. (2) Triggering mechanisms and levels for action, including both of the following:

   1. (A) Standard water shortage levels corresponding to progressive ranges based on the water supply conditions. Water shortage levels shall also apply to catastrophic interruption of water supplies, including, but not limited to, a regional power outage, an earthquake, a fire, and other potential emergency events.
   2. (B) Water shortage mitigation, response, customer communications, enforcement, and relief actions that align with the water shortage levels required by subparagraph (A).