Marin Water commercial and multi-family customers with an active potable water service can receive a custom rebate for implementing water-saving upgrades not covered through any other existing rebate programs. Rebate amounts are based on 50% of project costs (excluding tax and labor) or water savings demonstrated over a 12-month period, whichever is less. Rebates for water savings are based on $3 per billing unit saved (1 billing unit = 100 cubic feet or 748 gallons).