Continuity mistake: In the scene on the roof when the local hoodlum is attempting to take on the flying saucers you see the scene from two points of view. There are four people watching the local hoodlum getting fried. From the front, from left to right you see an old guy; a tall black guy; a women in pink and then a young guy with lots of hair. When seeing the scene from behind these watchers, you only see the old guy and the guy with the all the hair. Each time the angle changes the tall black guy and the women in pink are there.
Continuity mistake: UFO finds the toaster plugged into the bottom power outlet then leaves to get the other UFO. When they return 1 minute later the toaster is plugged into the top outlet. (00:23:25 - 00:24:25)
Continuity mistake: The female grey-coloured UFO swaps to bright orange coloured several times in the film whenever there's low light and a blue-screened image is superimposed against him. Check the moment it gives birth, for example.
Visible crew/equipment: When the "Father" UFO is flipping burgers, you can see the puppeteer's arm for a split second.
Revealing mistake: When Marisa has her back to her window and you see Mason tossing out his paintings you can see wires attached to the paintings.
Continuity mistake: When the 3 baby UFOs learn to fly they rest on a counter covered with sawdust. When Frank asks Harry if he revived the UFO the sawdust is gone.
Answer: It's been years since I watched this one, but here's an engineer's opinion. Yes on the electrical meters, no on the water. If you strike an electrical meter with sufficient force to dislodge it from the main electrical service contacts, the flow of electricity will stop. Striking a water meter with an axe might destroy the metering mechanism and cause a leak, but water will still flow. Only severing the metal water service pipes would stop the water, but that would also cause a major flood.