Really dangeous one, if you have a gas water heater like this you should be careful. Especially when placing it near sewing machine. They are can be real hazard for you, kids and pets.
You should have a safe house by eliminating all unwanted explosion source like gas and even fart. Adding security camera is also good to surveillance every activity in the house. You can see your kids do it right, not illegal and safe. For the safety information about some stuff, you can check http://vinitankless.biz/ and the proper way to use sewing machine with adel at http://adelsewing.biz/. Both of them is great. You can check it out later.