You might look into installing an atmospheric storage tank that would be controlled by a float switch that would control a solenoid valve to control the water flow into the tank. You would then need a pump to repressuirze the water and deliver it to your fixtures. That pump would need some type of pressure tank to enable it to shut off while you used water or, a very small one to stop water hammer and then the pump would run constantly while you used water. All pumps are basically rated continous duty so running while you use water is not a problem. That is better than repeated starts for very little water use.
Quality Water Associates