I’ll be Devil’s advocate. We had a rental heater through the utility company here in Kingston. One night, late on the wife noticed a trickle of water in the cupboard where the heater was. Determined it was from the heater. Quick call to the utilities emergency number, then a transfer and 30 mins later a plumber turns up, removed the old heater, installed a new one shipped in that evening from a depot. Didn’t finish until really late on that night. No charge to us.
Charge isn’t outrageous but that’s maybe because the local utilities company sources these things. The plumber said the heater was close to completely failing and if it had we would have had serious water damage.