The change means some customers could be asked to limit water use or pay more if they use beyond their allotment.
Many communities across Southern California have adopted water use regulations.
In Thousand Oaks, customers are asked to limit landscape watering to three days a week. In Agoura Hills, customers are charged for using water beyond their allotment. Simi Valley fines anyone found watering lawns during the day. Camarillo is drilling a new well off Las Posas Road, hoping to offset the 15 percent reduction.
California has experienced drought conditions the past seven years. Recent restrictions on the amount of water being pumped from Northern California have also contributed to supply shortages.