The water company doesn't care and is not legally responsible for anything that happens on the meter side of the cutoff valve. They are not going to spend a dime on anything else.
I would say you could hook one up yourself, off hand you would need the following:

A motorized valve of a size and coupling type compatible with your supply pipe. 120 VAC single phase with integral open and close limit switches.

A normally-closed pressure switch set at about 15 psi.

A DPST pushbutton switch.

[OPEN VALVE] A motorized valve will hold its position regardless of power. It must be electrically forced to move to a new position. By wiring the pushbutton switch to open the circuit to the pressure switch and closing the circuit to OPEN the motorized valve, with water supply pressure the system charges and pressure rises above 15 psi. Releasing the pushbutton, the pressure switch has opened and does not attempt to close the valve.

[VALVE CLOSES]When the water system pressure drops, the pressure switch drops out below 12 psi and closes the pressure switch contacts. This routes power to the close terminal of the motorized valve. When the valve seats, the limit switches open and protect the motor from burnout.

When water pressure returns, the valve remains closed, and the pressure switch is still sensing the house side of the water pressure, less than 12 psi. The valve remains closed.

To open the valve go back to [OPEN VALVE]

Something else that often happens when there is a loss of water supply pressure. Someone in the house will turn on both hot and cold water faucets and the electric hot water tank will siphon down and uncover the electric heating element. This results in burning out the electric heating element. The cost of a new element is typically $10 for a small hot water heater. But it's just a bother to replace it.

I've not heard of any similar problems with gas or oil water heaters.

It need not be electric, it could be done purely mechanically, using springs to supply the energy to close a butterfly or ball valve, and a pressure diaphram operating a trigger which releases the energy stored in the springs. Manually esetting the valve "recharges" the spring. As for a pressure drop in the house, your plumbing needs repaired, or at least the trigger mechanism could be adjusted to account for low pressure.