You may take anything not built-in or installed. So you could take a non-built in refrigerator, non-built-in microwave, the typical clothes washer and dryer, etc. But anything which is connected to the plumbing or hardwired into the electrical system is regarded as "fixture" and part of the house and goes with the home. This would certainly be the water heater; would be any dishwasher except one of those portable ones that do not permanently connect; gas stoves; etc. Taking things that are part of the home would constitute theft; and if you do any damage in removing anything, you could be sued for repair costs.