If you have a high water bill, it could be from a leak on your property.
Check for leaks:
Toilets: Open the back tank. Examine the overflow and adjust the ball float if needed. Place a few drops of food coloring in your toilet tank. Wait about 30 minutes without flushing. If the color appears in your toilet bowl, then you have a leak and need to replace the flapper valve or adjust the chain. Replacement parts are easy to pick up at your local hardware store. Turn off the water supply to your toilet while you are waiting for or conducting repairs.
Leaky faucets/showerheads/hose bibs: Check all of your faucets, shower or bathtubs, and hose bibs for drips. Even small drips add up.
Irrigation: Check your control valves and irrigation lines for breaks or leaks. If your system is on a timer, check that the timer is set correctly. Other common causes of leaks are water softeners (stuck valves), leaks at the water connections to sinks, and leaks in a swimming pool or pump.
The Santa Clara Valley Water District offers helpful water conservation guidance and tips. Visit their website at https://www.valleywater.org/saving-water/residential.