Multiple San Carlos residents are asking for City Council’s help in determining how their water bills have gotten so high, sharing frustrations over misleading notices and unprecedented spikes in rates. … Rates used to be tiered between 1-7 units at $7.24 a unit, 8-10 units at $9.05 a unit, and the highest tier was rated $13.5652 for use over 10 units. Now there are four tiers, with lower rates for lower units used. The new tiered system charges $3.45 per unit from 1-6 units, $13.73 per unit from 7-9 units, $17.16 per unit from 10-13 units, and $25.73 per unit above that.