While we have had a fixed service charge for single-family residential customers since 2011, it included three units of water and reflected the price of three units. It was not a true mechanism for covering fixed costs. Most water agencies include a fixed service charge and one or more tiers of quantity charges. They typically have different rates for residential, commercial, and irrigation customers. Inclining tiered rates for single-family residential customers are important to pass on the cost of meeting peak summer demands (e.g., running three treatment plants simultaneously instead of the one treatment plant needed during winter, installing larger diameter pipes, ensuring sufficient treatment, pumping and tank storage capacity).